# Deep Retro-fit.



## Pat Smith (12 Nov 2020)

We are undertaking a deep retrofit project on a 1970 detached bungalow. There is currently a subfloor that a builder is recommending we fit a new 150mm concrete floor on 100TF insulation on a Radon barrier. Is this the most cost-effective option What other options are there ?


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## Leo (12 Nov 2020)

I think that is the only way you can really get sufficient insulation into the floor, and without addressing the floor, you lessen the effectiveness of the rest of the work.


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## Micks'r (12 Nov 2020)

OP, I would be a bit concerned that you are asking quite a basic question on your deep retrofit project. If you have someone advising you then would they not be best placed to advise. If not, why not?

Agree with Leo above that the floor weakness needs to be dealt with. You do have another option and that is to insulate/airtighten the existing floor but this decision depends to a certain extent of what other measures you are undertaking. For deep retrofit to be successful you need to take a holostic approach and not look at one measure in isolation.

And to put in perspective what I'm getting at, I live in a deep retrofitted 1970's bungalow, which you couldn't heat past 18 degC when we originally bought it. It now takes very little energy to maintain a comfortable temperature and even overheats during a power outage when too many candles are lit. Yet, the one thing that was not touched for various reasons during the retrofit works was the original floor slab (still uninsulated).


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## Cricketer (12 Nov 2020)

Micks'r said:


> And to put in perspective what I'm getting at, I live in a deep retrofitted 1970's bungalow


I'm looking at upgrading the insulation in our 1960s bungalow. Could you give some details on what you focused on Micks'r?


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## Micks'r (12 Nov 2020)

Cricketer said:


> I'm looking at upgrading the *insulation* in our 1960s bungalow. Could you give some details on what you focused on Micks'r?


First off, while insulation is important, it's not the be-all and end-all its often made out to be. Very often too much emphasis on insulation and not enough (or none) on airtightness and ventilation.
So, you need to understand first the 3 forms of heat transfer (loss) i.e. conduction, convection and radiation and address each one with insulation, air tight measures and glazing options respectively. Also, as you add insulation the role and impact of thermal bridging (relatively high conductive material bridging your insulation layer) becomes very significant not only for heat loss but also potential for mould growth internally. Finally, you need to ensure sufficient ventilation is provided to exhaust the internally generated moisture from normal occupant activities.
So, what we did was
1. Tested the house for air tightness to understand all the air tight issues (>10 m3/hr/m2@50Pa). The weaknesses then were addressed in a methodical way and incorporated into any other improvements - basically all junctions and penetrations of the external thermal envelope were air tightened using a variety of air tight materials. Final test show huge reduction to less than 1 m3/hr/m2@50Pa, >90% improvement!
2. Whole house mvhr system installed in the attic space
3. 300mm cellulose pumped into the attic
4. 200mm rockwool ewi extending down 600mm below the finished floor and up past the soffit to meet the attic insulation. By going down past the floor and up past the soffit, the linear thermal bridges were pretty much eliminated and also the need to insulate the original concrete floor slab was mitigated (personally, I prefer a slightly cooler floor slab under my feet when everything else in the space is warm, ... I don't like underfloor heating for this reason). We went with 200mm ewi for 2 reasons: 1. we had a 450mm soffit so 200mm still left a 250mm soffit and 2. doubling the insulation thickness added only about 10% to the ewi cost.
5. Replaced all windows the ph certified units and installed them flush with the external wall outer surface so that the ewi overlapped the thermally broken frames, again eliminating the thermal bridges around the opes.


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## SPC100 (13 Nov 2020)

I agree with everything you have said and the detailing you mentioned. Would you care to name your advisor for that build?


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## Micks'r (16 Nov 2020)

SPC100 said:


> I agree with everything you have said and the detailing you mentioned. Would you care to name your advisor for that build?


I was the advisor. (I'm an engineer who has specialised in domestic heat loss mechanisms and solutions)


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## Alkers86 (17 Nov 2020)

Micks'r said:


> First off, while insulation is important, it's not the be-all and end-all its often made out to be. Very often too much emphasis on insulation and not enough (or none) on airtightness and ventilation.
> So, you need to understand first the 3 forms of heat transfer (loss) i.e. conduction, convection and radiation and address each one with insulation, air tight measures and glazing options respectively. Also, as you add insulation the role and impact of thermal bridging (relatively high conductive material bridging your insulation layer) becomes very significant not only for heat loss but also potential for mould growth internally. Finally, you need to ensure sufficient ventilation is provided to exhaust the internally generated moisture from normal occupant activities.
> So, what we did was
> 1. Tested the house for air tightness to understand all the air tight issues (>10 m3/hr/m2@50Pa). The weaknesses then were addressed in a methodical way and incorporated into any other improvements - basically all junctions and penetrations of the external thermal envelope were air tightened using a variety of air tight materials. Final test show huge reduction to less than 1 m3/hr/m2@50Pa, >90% improvement!
> ...


Few questions if you wouldn't mind, maybe we need a separate thread but sounds like a great project!


Once you got the house tested for airtightness (which I understand is a blower test), how did you go about identifying weaknesses in order to address them? I haven't come across anyone who provides such a service or even a decent guide of how to go about it.
 How did you continue your EWI above the soffit?
Could you name a supplier for passive house certified windows - what sort of a difference (performance & price) would you be talking Vs SEAI approved double / triple glazed windows?
Can you explain your window detail more? You moved the windows all the way forward to they're flush with the outer edge of the insulation? How did you install the windows in that case? Or you insulated over the window frames once they were installed?


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## Micks'r (17 Nov 2020)

Alkers86 said:


> Few questions if you wouldn't mind, maybe we need a separate thread but sounds like a great project!
> 
> 
> 1. Once you got the house tested for airtightness (which I understand is a blower test), how did you go about identifying weaknesses in order to address them? I haven't come across anyone who provides such a service or even a decent guide of how to go about it.
> ...


1. Yes, blower door used. With the correct weather conditions, a thermal imaging camera, trace smoker and, most importantly, an experienced surveyor/tester all major weaknesses are readily identifiable. As I do these surveys for a living, this was the easy part  .
2. Remove the soffit and continue the ewi up to top of the external leaf. Then, using earthwool or similiar, bridge the gap between the ewi with the ceiling insulation. We used a fully breathable ewi (rockwool) so it was straight forward to achieve. Supplemental attic ventilation was provided by coring the gable walls.
3. Can't name them here . I'm not aware of "SEAI approved" suppliers. The units are Passive House certified and were extremely competitive. I had my own builder install them though
4. No, they were flush with the outer edge of the original external wall leaf, then the ewi overlapped the frames thus eliminating the tb.


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## Alkers86 (18 Nov 2020)

Thanks for that, re: no.4, would installing the windows in their old position, prior to the ewi, not have an end result of more insulation over the window frames in any case? The ewi installers would hardly have left the frames bare in either position?


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## shweeney (18 Nov 2020)

everything I've read about EWI says that you should move your windows out to meet the insulation, but any houses I've seen with it done, they haven't bothered. How much of a difference does it make?


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## Leo (18 Nov 2020)

Alkers86 said:


> Thanks for that, re: no.4, would installing the windows in their old position, prior to the ewi, not have an end result of more insulation over the window frames in any case? The ewi installers would hardly have left the frames bare in either position?



You have to address cold-bridging and the condensation/ mould issues that causes. Moving them out eliminates those issues, but EWI installers are slow to do that as it's difficult to move windows without damaging them.


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## Micks'r (18 Nov 2020)

Alkers86 said:


> Thanks for that, re: no.4, would installing the windows in their old position, prior to the ewi, not have an end result of more insulation over the window frames in any case? The ewi installers would hardly have left the frames bare in either position?


By not moving the windows out you are left with a significant thermal bridge, the consequence of which is a real risk of mould formation internally on the reveal.
In addition, in out case of 200mm ewi plus 100mm external leaf, there would be an external reveal depth of 300+mm which both aesthetically and solar gain wise is poor. 
Also moving the windows out means that we have quite a deep internal reveal which can be useful.


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## David_Dublin (24 Nov 2020)

@Micks'r wonder if you can answer this, just an opinion, like "if it was my house...". Apologies for hijacking the thread, I will delete the post if not acceptable.

House is 1920s, 2 storey end of terrace, suspended wooden floors in hall & reception rooms, solid floor in return (not insulated at ground level), no insulation apart from some DIY rockwool in attic, red brick so EWI solution not an option.

Planning a refurb + 2 storey extension. Big focus on making it more snug. Includes attic conversion (so will resolve roof insulation). New windows throughout. Extension will probably have EWI, with internal insulation on existing internal walls. Need to re-wire, adding new bathroom, moving kitchen, new gas boiler (rads are good). Will need to dig out and insulate floor of return room at ground floor level.

Main thing I can't make my mind up on is the suspended floors. My inclination is that while gutting the house we should backfill the void in hall & reception rooms. Purpose is to stop draughts, improve insulation, avoid any rotting or rodent issues in the future. If we don't backfill, we'd probably need to lift the current boards and insulate/draughtproof - feels like a better option to backfill.

Wonder what you think about that choice?

If doing that, is it mad not to put in underfloor heating? Increasingly people will be spending more time in the house, working from home etc. I'm cautious of putting in UFH based on running costs, "heating always on" but it might be nice to have a reasonable ambient temp all the time. Not interested in A2W/heatpump, so it's likely to be gas powered. Note, we would have rads upstairs. We have a Nest so could potentially add another Nest and have UFH zone and Rad zone.

Are we mad to consider putting down all the backbone for good UFH and not do UFH? Would be nice not to have rads everywhere.


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## Leo (24 Nov 2020)

David_Dublin said:


> House is 1920s, 2 storey end of terrace, suspended wooden floors in hall & reception rooms, solid floor in return (not insulated at ground level), no insulation apart from some DIY rockwool in attic, red brick so EWI solution not an option.



Take a look at this guide, it provides decent guidance on what should be tackled first in terms of return on investment for a lot of the common Irish house types.


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## Micks'r (24 Nov 2020)

"If it was my house" I would take a fabric first approach. I.e. optimise the thermal envelope against heat loss and moisture buildup. Then I would ensure I'm adequately ventilated and only then think about how to supply the little amount of energy (heat) required to maintain a continuous comfortable temperature. Underfloor heating would not be part of my plans for personal reasons. I would then choose my professionals & contractor very very very carefully.

Existing house:

1. Do you have a target for air tightness? If not, why not? If you don't understand its importance, then research it until you do. This is critical. Special attention would be given to the attic conversion as these are well known to adversely affect the rest of the house when ignored. Any efforts to improve the insulation values of the thermal envelope fabric may well be wasted if the air tightness is poor. My air tight target would be <1 m3/hr/m2 which is 5 times tighter than current b.regs and I would be confident of achieving this in a refurb scenario.

2. I would thread carefully with the insulation specification especially on the external redbrick solid walls. Depending on what's there currently, I would likely use a thin diffusion open product on the internal of the  walls, such as Calsitherm. I would be paranoid about moisture buildup in my walls and also cognisant not to introduce unnecessary thermal bridging. I absolutely would insulate and air tighten my suspended floors but mightn't want to loose their character so how to do it would be open to debate.

3. I would ensure that appropriate ventilation is designed in early and perhaps included with that of the new build extension. A 1920's house suggests a number of chimneys. Chimneys are also known as passive stack ventilators. What are the plans for these? 

4. I would finally decide on my heating source and distribution system when I would have a far better understanding of what both my heat demand and heat load are likely to be. I would try to match the source with the distribution system (for example, low temperature source (hp) with low temperature distribution system (uf) etc) as well as taking some practical aspects into account such as who do I call in the future when (not if) my system develops a fault in the depths of winter and I need it sorted asap.

New extension:

Build passive. Simples


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## David_Dublin (24 Nov 2020)

Thanks a mill @Micks'r for such a brilliant/detailed answer.

This is all really valuable when we sit down with architect to ask him (slightly) informed questions to make sure all things airtightness, ventillation, insulation, heating are considered and thought through. Current planned architect is very bright, not certain how good he is on specifications for insulation, ventilation & airtightness - we just haven't got into the detail on this, but I have seen his drawing packs for builders and they are very detailed. If he doesn't want to get into the detail on this I can always get additional professional(s) to advise.

Re airtightness - I understand the importance....though until now I had kind of been ignoring a scientific approach as am conscious that chimneys & front door with single pane stained glass side panels and window does not play well with low air tightness scores. Herself is not keen on a porch to the front door so this is a challenge re airtightness.

I figured doing the floors, good windows, attic etc makes it much better, and was going to leave it there. But I take your point that being able to answer questions on heating is dependent on the approach to airtightness, amongst other things.

Re chimneys....we'll probably end up with only one "in use" fireplace.  The other chimney downstairs will become a stove, to be confirmed. Other chimneys are in 3 bedrooms, currently covered over (metal plate in fireplace opening to chimney).

I'm also quite concerned about thermal bridging and overall decisions on insulation in relation to this, as you have alluded to. We have solid concrete soffits/fascias, so that adds complexity I believe. We dont have any insulation on walls, internal or external. We also have "hip roof" I think it is called, another complexity. I figure by converting the attic, as well as gaining valuable space, we also gain by dealing with any airtightness/insulation that needs to be addressed.

I'm not 100% sure what you mean re build passive for the extension - the extension is largely half of an open plan kitchen/utility area, the other half being one of the current reception rooms.


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## Micks'r (24 Nov 2020)

David_Dublin said:


> I'm not 100% sure what you mean re build passive for the extension - the extension is largely half of an open plan kitchen/utility area, the other half being one of the current reception rooms.


Apologies, meant to say Passive House standard


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## Hooverfish (24 Nov 2020)

Leo said:


> Take a look at this guide, it provides decent guidance on what should be tackled first in terms of return on investment for a lot of the common Irish house types.


That's a great document, thank you for the link Leo. Though I just find it hard to actually believe that adding 100mm external insulation to 2 ft thick stone walls is actually going to do any good on a "Type 1" house like ours...


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## candor (25 Nov 2020)

Hooverfish said:


> That's a great document, thank you for the link Leo. Though I just find it hard to actually believe that adding 100mm external insulation to 2 ft thick stone walls is actually going to do any good on a "Type 1" house like ours...


I've talked with with a well versed conservation joiner on this who is in and out of many building like this. You've to be very careful when dry lining or insulating stone walls. The walls are designed to breathe so need to do so or damp and mould issues can result.


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## Leo (25 Nov 2020)

Hooverfish said:


> That's a great document, thank you for the link Leo. Though I just find it hard to actually believe that adding 100mm external insulation to 2 ft thick stone walls is actually going to do any good on a "Type 1" house like ours...



As per @candor's point above, you need to be careful with old stone dwellings. However, if you can envelop the walls within insulation and address bridging, the walls effectively become a thermal store, slowly heating as your heating system runs and later slowly releasing heat as the house cools.


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## David_Dublin (25 Nov 2020)

Are there "inefficiencies" or any other considerations I should be aware of with running UFH downstairs with standard rads upstairs? Or am I overthinking this?


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## Coldwarrior (25 Nov 2020)

David_Dublin said:


> Are there "inefficiencies" or any other considerations I should be aware of with running UFH downstairs with standard rads upstairs? Or am I overthinking this?


UFH generally runs at a lower water temperature than radiators, so you may need larger rads upstairs or aluminium ones especially designed for lower water temperatures.


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## David_Dublin (25 Nov 2020)

Coldwarrior said:


> UFH generally runs at a lower water temperature than radiators, so you may need larger rads upstairs or aluminium ones especially designed for lower water temperatures.



Bit confused about this. The boiler runs at one temp. If boiler is on its heating to that one temp. If the boiler is also responsible for heating hot water, then the temp it runs at needs to be considerably higher than UFH needs. Same argument for the standard rads.

I know the manifold mixes cooler water to ensure the water into the UFH is at the correct temp. Always thought this is inefficient - heating water to cool it down.

How woukd people generally heat hot water if they were UFH throughout. Are there smarter boilers that can be programmed to heat at different temps at different times?


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## Micks'r (25 Nov 2020)

David_Dublin said:


> Are there "inefficiencies" or any other considerations I should be aware of with running UFH downstairs with standard rads upstairs? Or am I overthinking this?


It can depend on the source of the heating.
If boiler such as gas or oil, then yes there are inefficiencies because you're heating up water and then cooling it down again (mixing it with cold water) for the uf. 
If a hp then as @Coldwarrior say above, larger or aluminium rads needed upstairs.

The main concern with mixing rads and u/f is though, imo, you are mixing a quick response distribution system with a slow response one. Also impacting this choice is the level of thermal mass available to utilise to help manage the temperature fluctuations and comfort. It can work well where you have a high thermal mass and u/f downstairs combined with maybe lower thermal mass and rads upstairs so it's not a simple question to answer without taking other aspects into account.


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## David_Dublin (25 Nov 2020)

Thanks @Micks'r that all makes sense. Seem like, if I am trying to keep things simple, then gas boiler heating water and standard rads is the way forward, even if I do the backfill of the void under the hall & reception rooms.


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## Coldwarrior (25 Nov 2020)

David_Dublin said:


> Are there smarter boilers that can be programmed to heat at different temps at different times?



Yes, there are gas boilers that can run at different temperatures for HW zones and heating zones, so say 65C for HW and 35C for heating etc.


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## Hooverfish (25 Nov 2020)

candor said:


> I've talked with with a well versed conservation joiner on this who is in and out of many building like this. You've to be very careful when dry lining or insulating stone walls. The walls are designed to breathe so need to do so or damp and mould issues can result.



Roundtower Lime (Richard Good-Stephenson from Lochplace) claim to have a product for this: [broken link removed] but I remain to be convinced. It says it's a base coat - I think that you'd have to use some sort of harling on top as well so I figure it would add 120mm to the house all round - not sure how that could be managed as the walls would then be wider than the Penrhyn slate roof...? The traditional small farmhouse windows have sills are 18 inches deep already so I think it would make the house a lot darker too.


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## candor (26 Nov 2020)

Interestingly, I couldn't quote your post @Hooverfish as the forum software thinks it's spam like in nature 

It's an area that I'm very interested in at the moment, as we are in the process of buying an old farm cottage. It needs renovation or rebuilding but I'm thinking of a sensitve renovation, provided it can be made comfortable.
I'll certainly look into that option, as we would likely need to replace the roof at some point and could factor that in. 
A simple way albeit not as energy efficient would be a hemp-lime plaster on both sides and plenty of insulation in the attic space. To heat the house  I'm thinking about a gasifying wood boiler.


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## Hooverfish (26 Nov 2020)

candor said:


> Interestingly, I couldn't quote your post @Hooverfish as the forum software thinks it's spam like in nature
> 
> It's an area that I'm very interested in at the moment, as we are in the process of buying an old farm cottage. It needs renovation or rebuilding but I'm thinking of a sensitve renovation, provided it can be made comfortable.
> I'll certainly look into that option, as we would likely need to replace the roof at some point and could factor that in.
> A simple way albeit not as energy efficient would be a hemp-lime plaster on both sides and plenty of insulation in the attic space. To heat the house  I'm thinking about a gasifying wood boiler.



Renovate if you can - that's what we did ourselves, 30 years ago, no regrets. Richard's given me details of plasterers who can come and talk to me about the job but of course, they are going to say they can do it no problem - whereas I'd love to find someone with an engineering background regarding thermal bridging etc. who has experience working on old houses, to get advice from. Let me know if you find one @candor . I did previously try to find an architect, but after initial enquiries to two or three, they are busy and seem mainly interested in well-funded public renovation projects, not so much the intricacies of trad. farmhouses and cottages and the SEAI/BER rules.


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## candor (27 Nov 2020)

Hooverfish said:


> Renovate if you can - that's what we did ourselves, 30 years ago, no regrets. Richard's given me details of plasterers who can come and talk to me about the job but of course, they are going to say they can do it no problem - whereas I'd love to find someone with an engineering background regarding thermal bridging etc. who has experience working on old houses, to get advice from. Let me know if you find one @candor . I did previously try to find an architect, but after initial enquiries to two or three, they are busy and seem mainly interested in well-funded public renovation projects, not so much the intricacies of trad. farmhouses and cottages and the SEAI/BER rules.



It is certainly what we are leaning towards, just have to take a good detailed look at the house. We are fans of preserving and enhancing what is existing if possible.

I'll let you know if we find someone in that regard. A good friend of ours is a semi retired architect that is pretty sensitive with projects like this.


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## Hooverfish (27 Nov 2020)

candor said:


> It is certainly what we are leaning towards, just have to take a good detailed look at the house. We are fans of preserving and enhancing what is existing if possible.


We found the guides that the Society for the Protection of Ancient Buildings in the UK produce to be really good regarding all building conservation issues. SPAB was founded by William Morris.


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## DublinHead54 (27 Nov 2020)

I've recently purchased a 1960's semi-detached with a BER rating of F, which is a bit surprising given the house is in much better condition than other properties I viewed with similar or slightly better BER. The house does not require a deep retrofit/renovation immediately, however, in 2 years we will probably look at the reconfiguration of the layout along the lines of combining the dining/kitchen and potentially building a first floor extension above the garage. Therefore, I am looking at the most efficient way for improving the efficiency of the house by doing relatively small jobs that will not be impacted by the longer-term works or essentially the biggest bang for my buck. 

This thread has shown the importance of airtightness which I had not really considered and had been considering the below

1. Replace the front door, it is the original wooden door replace with PVC or equivalent to give a better seal
2. Replace Front of house windows as it is old double glazing. Planning to only replace the front as the back gets good sunlight and due to future renovations they could potentially be impacted
3. Suspended Floors Downstairs - I was going to replace the current carpet with a good quality laminate and put the best insulation underneath and also seal with silicon or other sealant any air gaps between the floor boards and walls (is this safe?). I grew up in a house which had suspended floors and we put down a wooden floor, I don't remember it being uncomfortable or cold. 
4. Boiler / Radiators - The boiler is <5 years old but the radiators are old but overall the system seems in good condition, so I was going to consider replacing the radiators. 

I am now thinking I should get one of those airtightness tests, but not sure if I should just wait until I do the windows, front doors, floors as those will obviously be flagged as weaknesses. 

Any advice much appreciated!


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## Leo (27 Nov 2020)

Dublinbay12 said:


> I am now thinking I should get one of those airtightness tests, but not sure if I should just wait until I do the windows, front doors, floors as those will obviously be flagged as weaknesses.



Without a decent amount of work, a 1960's semi-d is likely to be too leaky to be able to perform a true air-tightness test. It might be like blowing into a sponge and trying to identify which holes the air is coming out through.


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## DublinHead54 (27 Nov 2020)

Leo said:


> Without a decent amount of work, a 1960's semi-d is likely to be too leaky to be able to perform a true air-tightness test. It might be like blowing into a sponge and trying to identify which holes the air is coming out through.



What equates to 'decent' amount of work. The other options I see are

1. Insulate between the floorboards, though I'd rather just seal holes and use good insulating underlay on ground floor.
2. Insulate the roof space
3. Insulate between the walls / or some form of internal wall insulation.


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## David_Dublin (27 Nov 2020)

I put a layer of really thin mdf, 6mm, on my suspended floors downstairs before putting down thick underlay (11mm), and deep pile carpet. I taped up all the joints, taped to skirts. Pretty much airtight by the time we put down the underlay and carpet. It has made the world of difference to the house.


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## Micks'r (27 Nov 2020)

Leo said:


> Without a decent amount of work, a 1960's semi-d is likely to be too leaky to be able to perform a true air-tightness test. It might be like blowing into a sponge and trying to identify which holes the air is coming out through.


It is these types of houses where the air tightness test comes into its own. Tested a house yesterday well north of 15 m3/hr/m2 and the top 3 issues found, when sorted, will go a long way to cutting the leakage by at least 2/3rds. And, none of these issues were obvious to the owner before the test.


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## Micks'r (27 Nov 2020)

Dublinbay12 said:


> I am now thinking I should get one of those airtightness tests, but not sure if I should just wait until I do the windows, front doors, floors as those will obviously be flagged as weaknesses.
> 
> Any advice much appreciated!


My advice is if you're going to have the survey / test done anyway, have it done sooner rather than later. The value of having it done it not just in finding and quantifying the issues but also in outlining the possible solutions which you may be able to incorporate into other home improvements projects. 

Finding out too late that there is an issue after you have already done some work in an area is not ideal. A good example of this is where people think their windows are an issue because they feel draughts and plan on having them replaced. In a very lot of cases it is found that the actual windows can be generally fine but the issue is how they were initially installed which is the cause of the draughts. Often then replacing the windows does not address the real issue. While this is just an example, it shows that knowing ahead of time what to look out for is key to planning improvements.


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## SPC100 (27 Nov 2020)

Micks'r said:


> It is these types of houses where the air tightness test comes into its own. Tested a house yesterday well north of 15 m3/hr/m2 and the top 3 issues found, when sorted, will go a long way to cutting the leakage by at least 2/3rds. And, none of these issues were obvious to the owner before the test.



That's really interesting. Would you mind detailing what the three top issues in that house were?

I'm guessing things like External doors? Light fixtures? Floors?


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## DublinHead54 (28 Nov 2020)

How much should one of these tests cost?


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## Micks'r (28 Nov 2020)

SPC100 said:


> That's really interesting. Would you mind detailing what the three top issues in that house were?
> 
> I'm guessing things like External doors? Light fixtures? Floors?


No.1 by a country mile was the t&g timber ceilings in several areas
Next was several (5no) crawl space access doors/hatches (it was a dormer)
No.3 was upstairs floor and floor to knee wall junctions (as often occurs in these cases, the upstairs carpet lifted a couple inches off the floor  due to the pressure of the incoming air)


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## Micks'r (28 Nov 2020)

Dublinbay12 said:


> How much should one of these tests cost?


Expect to pay in around 5 to 600 to include a comprehensive report


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## Leo (30 Nov 2020)

Dublinbay12 said:


> What equates to 'decent' amount of work. The other options I see are
> 
> 1. Insulate between the floorboards, though I'd rather just seal holes and use good insulating underlay on ground floor.
> 2. Insulate the roof space
> 3. Insulate between the walls / or some form of internal wall insulation.



Don't confuse insulation with air-tightness. For suspended timber floors, you would need to lift them insulate and seal all joints and around all edges. After that, look at all the obvious leakage points like external doors and windows, attic hatches, skirting, electrical fittings, switches, and all points where cables or pipes travel through walls or ceilings. Look for any cracks in walls or ceilings. To me, unless you address all of the above, an air-tightness test is a waste of money.


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## Alkers86 (30 Nov 2020)

Micks'r said:


> Expect to pay in around 5 to 600 to include a comprehensive report


What sort of reduction in a heating bill would you experience going from 1960s level air "tightness" to a decent standard nowadays, everything else being equal. €5-600 would almost cover our gas bill for a year.


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## David_Dublin (30 Nov 2020)

Leo said:


> Don't confuse insulation with air-tightness. For suspended timber floors, you would need to lift them insulate and seal all joints and around all edges. After that, look at all the obvious leakage points like external doors and windows, attic hatches, *skirting, electrical fittings, switches, and all points where cables or pipes travel through walls or ceilings*. Look for any cracks in walls or ceilings. To me, unless you address all of the above, an air-tightness test is a waste of money.



Here's what I don't understand. You go to this level of detail, and then drill bloody great holes in the walls as vents. What's the point? I understand if you're intending to build to passive house standards, to mechanical ventilation etc. But if not, why bother going beyond sealing floors, doors, windows?


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## Micks'r (30 Nov 2020)

Leo said:


> To me, unless you address all of the above, an air-tightness test is a waste of money.


I find the opposite because prior to the test, the owners are unaware to the extent of the leakage rates and the impact these are having on their heat loss. A also find the test itself is a definite "eye opener" and have been told this on a very frequent basis.


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## Micks'r (30 Nov 2020)

Alkers86 said:


> What sort of reduction in a heating bill would you experience going from 1960s level air "tightness" to a decent standard nowadays, everything else being equal. €5-600 would almost cover our gas bill for a year.



... how long is a piece of string... it depends on a whole lot of things not least how warm you keep the house in general. What I find It quite often especially in cases where there is high air leakage to start off with is that some of the heat retention improvement dividend is absorbed in a warmer home i.e. the house is allowed to get a degree or two higher for longer because there is less perception of waste. 

Where the test/survey is really valuable, I think, is it takes the guesswork out of where to spend your money or not.


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## Micks'r (30 Nov 2020)

David_Dublin said:


> Here's what I don't understand. You go to this level of detail, and then *drill bloody great holes in the walls as vents*. What's the point? I understand if you're intending to build to passive house standards, to mechanical ventilation etc. But if not, why bother going beyond sealing floors, doors, windows?


You don't. "hole in wall" vents are proven time and again to be not fit for purpose in any kind of reasonably airtight house (say <5 m3/hr/m2@50). You generally need some form of a properly designed mechanical ventilation system. 
In my opinion and given our moderate climate, this is still a major flaw in our building regulations.


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## David_Dublin (30 Nov 2020)

Micks'r said:


> You don't. "hole in wall" vents are proven time and again to be not fit for purpose in any kind of reasonably airtight house (say <5 m3/hr/m2@50). You generally need some form of a properly designed mechanical ventilation system.
> In my opinion and given our moderate climate, this is still a major flaw in our building regulations.



What sort of cost are you looking at for mechanical ventilation? 4 bed, 1800sq ft. Any ideas?


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## Micks'r (30 Nov 2020)

David_Dublin said:


> What sort of cost are you looking at for mechanical ventilation? 4 bed, 1800sq ft. Any ideas?


It's nearly like asking what sort of cost for a family car there's so much it depends on but anything from 1.5 to 6k I would think.


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## David_Dublin (30 Nov 2020)

Micks'r said:


> It's nearly like asking what sort of cost for a family car there's so much it depends on but anything from 1.5 to 6k I would think.



Thanks. I kind of knew it was a bit of a daft question. Feels like peeling an orange this refurb stuff. Like, you could go with not spending too much on airtightness, or ventilation. But if you go bananas on air tightness then you need to actively solve for ventilation issues that creates. I know the ultimate output of the more expensive approach is far superior...cheaper to run, healthier, more env friendly etc. But if it adds 20k to the price tag, its a fair chunk of change in overall budget.


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## Micks'r (1 Dec 2020)

David_Dublin said:


> Thanks. I kind of knew it was a bit of a daft question. Feels like peeling an orange this refurb stuff. Like, you could go with not spending too much on airtightness, or ventilation. But if you go bananas on air tightness then you need to actively solve for ventilation issues that creates. I know the ultimate output of the more expensive approach is far superior...cheaper to run, healthier, more env friendly etc. But if it adds 20k to the price tag, its a fair chunk of change in overall budget.


For sure. you need to strike a balance but be certain you don't solve one problem and create another especially when it come to moisture control. 
That's where a targeted approach based on an in-depth examination or survey of the building comes into its own plus an understanding that there are always compromises to be made especially when it comes to budget. The key is to make the correct decisions based on relevant information / data.


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## David_Dublin (1 Dec 2020)

Thanks Mick. Last questions.....I think! For a significant refurb, presume you're doing the examination rather than survey? i.e. you have a target for airtightness, then plan and design with architect (and any other professional as required) based on this, and then design ventilation solution appropriate.

I can see now how important it is to get the design and plan stage right, and then the execution - for a thorough refurb there is no airtight test possible/relevant until most of the work is done, at which point the work in relation to airthightness would already need to have been factored in.


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## Leo (1 Dec 2020)

David_Dublin said:


> Here's what I don't understand. You go to this level of detail, and then drill bloody great holes in the walls as vents. What's the point? I understand if you're intending to build to passive house standards, to mechanical ventilation etc. But if not, why bother going beyond sealing floors, doors, windows?



There's a balance between effective ventilation and lots of uncontrolled leaks resulting in drafty rooms. But you're right, going all out and spending big money on achieving air-tightness is a waste of money without mechanical heat-recovery ventilation.


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## Leo (1 Dec 2020)

Micks'r said:


> I find the opposite because prior to the test, the owners are unaware to the extent of the leakage rates and the impact these are having on their heat loss. A also find the test itself is a definite "eye opener" and have been told this on a very frequent basis.



I'd consider charging €5-600 on a test to point out the obvious as veering dangerously towards an exercise in gouging. It would be far better if people were educated on how they can spend less money on fixing a few of the most common issues.


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## Micks'r (1 Dec 2020)

Leo said:


> I'd consider charging €5-600 on a test *to point out the obvious* as veering dangerously towards an exercise in gouging. It would be far better if people were educated on how they can spend less money on fixing a few of the most common issues.


To point out the obvious? That's the whole point, it's not obvious to the average person where the real issues are and how to address them. This is what I'm told by clients on a very regular basis. Comments such as "you have completely changed my thinking on where my problems are" are not uncommon. 

On the gouging question, when you consider that travel time to and from a property of say up to 4 hours, 6 hours for the survey and discussion with the home owner on best way to proceed plus the writing of the bespoke report (3 hours min in the office) then possible followup phone consultation (included in the price) into the future, I'd argue that it is in fact very good value for money. Also include in the equation insurance / equipment maintenance, calibration & depreciation / other fixed costs / profit plus the fact that a proper survey can only be done effectively during the heating season. One thing's for sure, I ain't getting rich from my "gouging".

Yes I agree, education is key especially for homeowners who should then demand better standards from the industry. Problem is though that the construction industry is riddled with conflicts of interest so who does the educating of the public?


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## Leo (1 Dec 2020)

Micks'r said:


> To point out the obvious? That's the whole point, it's not obvious to the average person where the real issues are and how to address them.



It should be obvious to anyone working in this line  that a 50 year old suspended timber floor is going to be a major issue. Likewise with old poorly fitting loft hatches, poorly sealing windows and doors. All these elements are factored into the BER calculations with sufficient accuracy from a visual inspection without no need for expensive blower tests.


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## Hooverfish (14 Dec 2020)

Just discovered this very interesting document about BER ratings and practicalities for historic houses, published by the Irish Georgian Society which may be of interest to @candor [broken link removed] - @Leo and @Micks'r may be interested to see that they do recommend ventilation tests in one of the papers because this is often the most efficient thing you can do in a historic building - but they also point out things like, the U-ratings are a big underestimate for old stone walls as they do not factor in 60 cm v 20 cm thickness for example (Historic Scotland tried to produce a proper set of U-ratings for old houses, but the civil servants in the UK rejected their calculations).


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## candor (14 Dec 2020)

Thanks @Hooverfish , I will certainly check that out.


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