# Insulating & Drylining 150 year Old House



## lp_6

Hi all,

  I’m another first time poster & could really do with some advice/guidance regarding insulating & drylining an old stone house (over 150 years old). The walls are solid stone and are pointed on the outside so I’m afraid external insulation isn’t an option for us. I have spent weeks researching this on the net but have found that a lot websites seem to contradict one other in their recommendations so I am wondering if anyone has had any personal experiences with a similar type of building?


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## davidoco

[FONT=&quot]Personal experience.  
2 foot stone walls, drylined using 3 x 2 timber stood back from the wall slightly using metal clips, foil backed plasterboard.  infil the 2" with whatever insulation takes your fancy, I used aeroboard for what it's worth.  I do on very windy days get a lot of air infiltration in and around the walls but I think it's a good trade off and that air clears out any moisture that may have accumulated.  

Absolutely no problems with damp although I have the outside fully french drained.[/FONT]


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## lowCO2design

my preference is for a hemp lime with lime render, it can be place internally or externally or both. use natural insulations such as hemp or sheep-wool in the attic, if your changing the windows try to integrate insulation around the reveals and also consider your ventilation strategy generally.


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## seantheman

How about this? http://www.youtube.com/watch?v=gsxeNmktNEs no connection.


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## threebedsemi

Firstly, there are many issues with drylining, as the following link explains. Take the time to read through the articles:

[broken link removed]


The second important thing to realise is that building of this type was designed to 'breath' ie it used lime mortar to allow moisture to travel through the walls to the outside. If the stone has been re-pointed in the past 10-20 years, it is almost certainly repointed with a cement based mortar, which will trap moisture within the wall. So you need to have the existing structure inspected by either an experienced consultant or a plasterer who is familiar with lime based plastering and pointing.

lowCO2design makes a very useful suggestion with regard to the system which may be used, either internally or externally.

Thirdly, and without having seen the building, from an aesthetic point of view many old houses were built of stone (out of necessity) and were then finished in a lime plaster. The stone wall behind was not built to look good, just to stand up and be hidden by the lime plaster.
I have seen a lot of buildings revdeveloped in the past 15 years where someone hacked off the original plaster, said 'ooo, look - stone! stone is nice' and proceeded to leave rather bad looking stonework exposed and to re-point it in an inapropriate manner.
Many of these buildings do not look good, and the stonework should really have been replastered with a breathable lime based plaster.

So, I would suggest that you might still consider external insulation, and perhaps expose some of the stone internally instead?

www.studioplustwo.com


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## lowCO2design

+1 with TBS above, 


if its not cut stone, it was not meant to be seen, and will potentially let in the elements/ moisture, to sit and fester behind your proposed dry-lining
the attached article explains the issues of dry-lining, and interstitial condensation, but I worry not many people appreciate how this translates to old buildings, especially given the chances of organic materials in the existing wall structure.
lately I'm trying not to use the word 'breathable' as Joe public assume this means the wall fabric is adequate 'ventilation' which its not.


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## seantheman

Are you guys, TBS and LowCO saying that the method shown in the Isover clip is flawed?


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## Superman

OP,
firstly, are you sure it is worth drylining at all? With old buildings, it is more important to ensure the walls are dry.  Their natural insulation values are significantly increased. So make sure that gutters and downpipes are in good condition and that the external ground level is well below floor level.

If it were me, I´d do some calculations on the existing house to see if it is worth messing with the walls.  Often the best thing to do is draught proofing, zoning the heating, putting in some heating controls and new boiler, and consider roof insulation.

After that look at external insulation with a breathable external insulation - I don´t understand why you suggest that the existing wall won´t allow this.

After that Calsitherm Klimaplatte is the best internal insulation for u values and breathability


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## threebedsemi

seantheman said:


> Are you guys, TBS and LowCO saying that the method shown in the Isover clip is flawed?


 
Well for a start, the isover video says that the moisture layer is 'optional' and in my opinion it is vital. Other than that, it seems a handy enough drylining system. ill look over the video again sometime and might comment then.

Superman makes a very valid point. If your walls are say 400mm thick, there is some thermal resistance there, so they will keep in some heat and the house will feel warm enough once it heats up. This is likely to take quite some time as there will be a lot of stone to absorb heat.

The advantage is that you have a huge thermal mass, which means that when you finally do get the house warm, it will stay at a pretty steady temperature for a considerable period. 

One disadvantage of drylining is that you are ignoring the thermal mass of the wall behind - thus you will heat up a room far quicker, but once you turm off the heat the temperature will drop back down a lot faster.


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## lowCO2design

Superman said:


> OP,
> With old buildings, it is more important to ensure the walls are dry.


 totally agree


> I´d do some calculations on the existing house to see if it is worth messing with the walls.


  it will be worth insulating the wall to retain the heat and to improve the surface temp of the internal wall face.





> Often the best thing to do is draught proofing, zoning the heating, putting in some heating controls and new boiler, and consider roof insulation.


absolutely, imo fabric improvements should always come first. + the one thing often forgotten when insulating/air-tightness/heating is the the need for good ventilation/ air movement.


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## lowCO2design

threebedsemi said:


> Well for a start, the isover video says that the moisture layer is 'optional' and in my opinion it is vital. Other than that, it seems a handy enough drylining system.


 +1 my preference is for the hemplime as its 'breathable', low carbon, and retaqins the thermal mass properties TBS talks about 


> Superman makes a very valid point. If your walls are say 400mm thick, there is some thermal resistance there, so they will keep in some heat and the house will feel warm enough once it heats up. This is likely to take quite some time as there will be a lot of stone to absorb heat.


apart from the thermal mass, a stone wall is a stone wall its thermal resistance is nothing compared to that of even 20mm of cork, hemp, mineral wool, any insulating material, and you'd want a cheap source of fuel to heat an uninsulated stone wall building. my experience/ fear of insualting the attic alone, brings a potential increase in surface condenastion elsewhere especially on the cold stone walls, probably behind furniture etc in rooms away from the main living/max heated space





> The advantage is that you have a huge thermal mass, which means that when you finally do get the house warm, it will stay at a pretty steady temperature for a considerable period.


I think 'finally' is the word here


> One disadvantage of drylining is that you are ignoring the thermal mass of the wall behind - thus you will heat up a room far quicker, but once you turm off the heat the temperature will drop back down a lot faster.


that and the potential for interstitial condensation - will the OP tape and seal a vapour control layer at floors, ceilings, windows etc in an old house..


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## lp_6

Hi all,
Thanks so much for the all of the above advice.

The reason we cannot use external insulation is because the walls are cut lime stone & there is also a protection order on the external walls.

We have been NON STOP researching this & are leaning towards the following process:
Lime plaster directly onto internal face of stone walls
100mm battens with 100mm of sheeps wool insulation in between
Vapour control layer (Intello or similar)
50mm counter battens
breathable plasterboard
lime plaster finish
breathable paint

Is this overkill? We would be very keen on using hemp but not really sure how the process is carried out? Is it just hemp plaster straight on to the stone? No Cavity? Budget is tight but at the end of the day this is probably the most important thing we could spend our money on.


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## Superman

lp_6 said:


> Hi all,
> Is this overkill? We would be very keen on using hemp but not really sure how the process is carried out? Is it just hemp plaster straight on to the stone? No Cavity? Budget is tight but at the end of the day this is probably the most important thing we could spend our money on.


There is no cavity with hemp lime.  Plaster straight on.  You need someone who knows what they are doing and there is a limit to how much you can plaster - maybe 60mm. 
Sheep's wool would achieve a higher value - especially if you can make it 100mm deep.  
I don't understand why you are proposing cross battens in your build up.  Is it to run electrics?

EDIT: the only way to tell if it is overkill is to get a very competent BER person or passive house designer to run the numbers on the cost/savings.


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## lowCO2design

[broken link removed]

no connection. cost will depend on who is doing the labour, the access and details etc



it is worth considering what the external finish is - if its concrete plaster then id be leaning towards calcium silicate boards - here's one Irish suppler  http://www.ecologicalbuildingsystems.com/products/climate-board/calsitherm-climate-board/
these are more expensive than than standard dry-lining 

but do note if pricing, price like with like: your conservation build if 'drylined' would use metal studs, mineral wool batts, complete Vapour barrier and paper less boards


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## chicote

Hi
I am about to start renovating a 130 year old Georgian house in Phibsboro...I have been told not to dry line/plsasterboard it as the red brick needs to breathe, the builder however reckons the house will be like a fridge if I do not dry line....would calcium silicate boards be suitable for this type of house? The only negative seems to be that they would make the room smaller I think apart from increased costs....any recommendations would be greatly appreciated!


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## JJDoherty

chicote said:


> Hi
> I am about to start renovating a 130 year old Georgian house in Phibsboro...I have been told not to dry line/plsasterboard it as the red brick needs to breathe...any recommendations would be greatly appreciated!



Hi Chicote,

We have an Edwardian terraced redbrick and had the same concerns as you regarding the redbrick with lime mortar. I found a plaster who installed an insulating product called Gutex Thermoroom, which is "breathable", to our externally facing walls, having first removed the original plaster. The walls were then re-plastered with lime. That was just over two years ago and worked well, making the rooms warmer and the finish is great. We repainted using a "breathable" paint too. 

Hope this helps...


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## chicote

Thanks JJ. That is helpful. Can I ask how much this cost?


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