# Insulation for 1950s house with poor BER rating.



## z101 (22 Nov 2009)

A friend of mine has recently moved moved into a 1950s mid tereace house. The surveyor suggested pumping insulation within cavity between the houses on either side for insulation. There is no insulation in the roof or in the external walls front and back.
Anyone any suggestions or knowledge as to where to start and what to do with this house to get maximum insulation without going nuts on cost.??


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## onq (23 Nov 2009)

Attic. Windows. Doors. Chimney. Porch. Walls.

ONQ.


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## colm5 (23 Nov 2009)

Depends on the construction. Pumped cavity for the front and back walls would be good, and you can get a grant for it. Side walls of a terrace house I'm not sure of ,as there may be wiring etc..
If its cavity block, different story.

Fully insulate the attic, should cost < 500euro, and there is a grant of 250euro. Many different systems available depending on the attic type.

A general rule is keep air infiltration to a minimum and insulate correctly.

Check SEI.ie for home energy saving scheme and grants available.


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## z101 (23 Nov 2009)

Thanks folks. ONQ can you elaborate slightly? For example how do you insulate the chimney or porch?
There is no cavity on external walls so cant pump there, but is a cavity in between adjoining houses apparently. 
If other area's are done would the 2 external walls be Ok as they are? Clearly the attic needs insulation. The windows are double glazed by the way. What attic systems are there? How do you stop air infiltration?


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## onq (23 Nov 2009)

Ceatharlach [what's that in English BTW?] 

Firstly let me say that you would be well-advised to check, before you do anything to the house, whether the building 

is a protected structure
is located in an architectural conservation area or 
is located in an area of special planning control.

Secondly, you asked the following question:

_"...what to do with this house to get maximum insulation without going nuts on cost"_

I responded with a list of items to attend to, loosely arranged in decreasing order of effectiveness and assumed increasing cost


Attic
Windows
Doors
Chimney
Porch
Walls

These translate as follows; -

Attic
Insulate, but ensure that you leave - or have newly installed - adequate ventilation. This is probably going to give you the most "bang for your buck".

Windows/Doors
These are really the one thing - replace the things filling the holes in the external envelope with new things that are better insulated and well-sealed.

Chimney
This is a bit obtuse I'd have to admit. There are "yokes" you can get to seal the chimney, the biggest source of infiltration loss in a house, a massively oversized hole with a flue effect sucking all the heat out of the house.
The implication is that you should fit some other kind of heating system for year-round use and don't use the chimney.
Apparently you can get removable "yokes" so you can have a traditional fire at Christmas or whatever.

Porch
A new porch in conjunction with the new door will massively reduce infiltration losses and moderate mass air movements through the biggest hole in the house - the front door.

Walls
Walls in traditional masonry building have to be allowed to continue to breathe.
Do not render them with cement based render on the outside and stick foil backed insulation on the inside
These measures will tend to trap moisture within the structure, which can manifest later as damp patches - there are alternative methods of insulation.

I attended Plan Expo 2009 this month and listened to Padraic Davis of MCO projects speak about his work on refurbishing older buildings.
He recommended the use of sand-lime boards and showed empirical studies that suggest heat loss through the walls could be reduced by 50%.
However he cautioned that using more insulation than that provided by a two inch board could cause problems with the way the walls dealt with moisture. 
It seems that you can have too much of a good thing, where older buildings are concerned and this should give us all pause for thought as we strive for carbon neutral buildings by 2013.

Herewith the link to the transcript of his Plan Expo talk on the Construct Ireland website:

[broken link removed]

If you intend to do both walls and roof consider the eaves detail carefully in terms of both

(i)  continuance of the insulation/avoiding cold bridges and
(ii) maintaining or providing sufficient ventilation to properly vent the attic.

The attic will be colder after the insulation is installed, with greater risk of interstitial condensation.
This will also increase the risk of burst water pipes through frost action, so these should be lagged at the same time.
Finally consider renewing any existing water tanks, fitting new insulated covers and surrounds but no insulating under them.

FWIW

ONQ.

[broken link removed]


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## AlbacoreA (24 Nov 2009)

Whats adequate ventilation in the attic. I think I have a draft in the wall and I was thinking its coming from the attic.

Also those gas vents. Is there a better way?


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## onq (25 Nov 2009)

AlbacoreA you jumped in without giving any information about the house you're asking about and I have a few comments.

Adequate means - sufficient to prevent a build up of moisture degrading building materials and insulation, but not so plentiful that air-borne water droplets find their way in and cause dampness in the attic.
Drafts "in walls" seldom come from attics.
What gas vents are you talking about?

Please reply here.

ONQ.


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## threebedsemi (25 Nov 2009)

I would advise you to get an energy audit carried out on your property - by someone who knows what they are doing- prior to proceeding. 

Further to onqs’ point regarding moisture being trapped in walls, this can become a serious (and unseen) problem when upgrading insulation levels to old walls.
It is possible to have a ‘dynamic moisture transmission calculation’ carried out (and certified) by a competent energy assessor which will give you peace of mind in this regard.

The air-tightness of your house will become very important as your insulation levels increase, and should be upgraded at the same time if at all possible.

You can also check the SEI home page for U-value calculators and payback estimators for various insulation upgrades.


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## z101 (25 Nov 2009)

How can you make a house airtight when you have external vents in walls in rooms not to mention a chimney??

How do you provide ventilation in the roof ong?

Ceatharlach means 'four lakes' and is the Irish name for Carlow.. Could rename the country ceatharlach at the moment..


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## threebedsemi (25 Nov 2009)

Ceatharlach,
regarding airtightness, here are a few straighforward measures:
- fit one of the 'yokes' referred to by onq in an above post to each of your fireplaces.
- remove or seal up your letter box and fit an external post box if possible.
-ensure that your windows and doors are airtight, seal around openings with chaulk or silicone as required, which can be done when drylining.
- ensure that your trap door has a tight seal (and is insulated!) with the supporting roof timbers.

With regard to the hole-in-the-wall vents, the only option to remove these, afaik, is to block them up and fit a passive-stack ventilation system to the house. this would entail considerable digging-around, but may be feasible if you are carrying our other woirks at the same time.


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## onq (25 Nov 2009)

Can I say that what  suggests seems to make sense - except I would be wary of attempting to seal an older property to that degree.
Wary does not mean I wouldn't do it though, but I'd make sure I understood the technology used in the build and the level of insulation in the original design as well as any later additions.

The reason for this is that firstly, sealing a house removes the "natural" interstitial draughts/gale force winds in the lounge we all used know and love when we were growing up in older properties. 
Thus there is more moisture to deal with inside the house.

Secondly, insulating the house must be done evenly, in the sense that highly insulating one part of the house can make another seem relatively colder.
A place that previously didn't have a problem may experience the effects of damp through condensation on colder surfaces.

I think the energy audit suggested by  is an excellent idea.
You should couple this with an overall set of proposals for upgrading the property in an integrated way in a properly sequenced upgrade. 

Some things just go together, for example:

Passive insulation measures can be installed any time.
However insulating an attic at 1st floor ceiling level means that the rest of the space above the insulation level gets proportionally colder.
This is because most of the heat that used to escape into the attic is now held in by the insulation.

Insulating without installing a vapour check of some kind on the warm side will allow warm moist air from below to migrate into the attic space.
As it passes through the insulation layer this is likely to turn into cold damp air.
This may in turn end up depositing moisture on these colder surfaces up there and in the top layer of the insulation.

So the attic may in fact need more ventilation than it originally had.
You can install this either by adding vent tiles or slates to the roof or Glidevale or similar vent to the eaves. 
The idea is to get cross ventilation if possible, and ventilate both at high and low level on the roofscape to help promote air circulation.
Its stands to reason then that after insulating at ceiling level you have to insulate service pipes and the water tank, but not beneath the tank.

Insulation of items like wall should include all the external envelope that is classed as "wall".
This means the window reveals must be insulated at the same time as the wall surfaces.
Otherwise they'll likely become cold and attract condensation.
Insulation can be internal or external but watch for cold bridges at the usual critical junctions



Eaves
Ope Head
Ope Sill
Threshold


There is littler or no point installing a MVHR system in an unsealed house - it'll run very inefficiently.
There is no way you should tightly seal an old house without installing an MHVR system - how would you vent it?

BTW before you do any "new" sealing of the house, have it pressure tested as is.
One of the speakers at Plan Expo 2009 - I think it was Joseph Little Architect- produced some empirical test results.
1940-1960's houses built using the old wet plaster finish on internal walls fared far better than might have been expected.
I think they had had new windows and doors fitted and perhaps the vents had been all taped up for the duration of the test.

Unfortunately Part F of the Building Regulations still has to catch up with Part L and also Appendix Q of the DEAP documentation.
Houses need permenant vents to habitable rooms - in Theory.

BTW Catharlach, I think its either Céadlach or Aonlach by now [either hundreds of lakes or they've all joined up into one lake].



ONQ.


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