Insulating an inside wall with wool

[HelenS]

Hi there,

I have just joined and this is my first post, also very "new " to old buildings so please forgive my lack of knowledge, but I am very keen to learn.

We live in a house that was built approx 1650 (it actually appears on an old map). It was originally a timber frame with pink sandstone at the bottom and has had later additions. We bought our house about 2 years ago because we loved it so much, not understanding that the cement and stone render on the outside or the spray foam insulation in the loft, wet cellar etc etc could such an expensive nightmare to sort out. It is not listed. This beautiful house is like a naughty school child and keeps missbehaving.
We, like many others, are on a tight to non existent budget. This means that we have to put right what is going wrong at the time rather than start with a logical plan.
After a leak in one of the uppstairs bathrooms we decided to "gut" it and start again. We removed 3 layers of floorboards, riddled with wood worm holes, so called in a company to spray the very large, uneven joists that are left. We uncovered the original wall behind plaster board but unfortunately the timber frame has also been attacked and the lath and plaster cover to the bricks is in very poor shape.
I found a contractor who works with lime and he will sort out the loose mortar on the internal brickwork.
After all of that waffle my question is how best to insulate the 2 external walls and sloping ceiling. The more investigating and research I do the more I become confused. I have been advised to leave a 25ml air gap, then errect a metal frame work and apply 100ml of sheeps wool (I have already bought this), then apply a moisture check plaster board and normal gypsom plaster. I will also fit an extractor fan I realise that I will need to remove the outside render but, due to lack of funds, won't be for a while.
Does this sound like a sensible way to do the insulating?

Thank you in anticipation xxx

 

[glayzell]

on my house, which is timber framed, i used thermafleece, and kept it in place/ creating an airgap using a breathable mebrane and the plaster laths on the other side... All seem to be working fine for me. I dont have any experience of using 'raw' sheeps wool...

 

[HelenS]

Thanks for your reply. I've heard about using a breathable membrane, someone suggested Du pont Tyvek Housewrap but on their website it does not say that you can use it onto bricks, as it is in this part of the house.
I think I'm going to be addicted to this website, I've spent hours reading the forum and articles already!
Helen

 

[jocelyn plummer]

I think I'm going to be addicted to this website, I've spent hours reading the forum and articles already!

Welcome Helen, join the clan! So glad you have enjoyed all the fun, good advice, cryptic comments etc. See you at the next PPUK gathering then :?:

 

[c r]

Hi

I'm not quite sure if this would help in your situation or not, but wondered about this product (perhaps to ''sandwich'' over the wool, before finally plastering over?)

http://www.lime.org.uk/products/boa...dingwood-wool-board/buildingwood-wool-boards/

Theres some more information on using it (and a similar product- 'Heraklith') in this previous thread:

http://www.periodproperty.co.uk/for...=10914&p=134349&hilit=lime+plastering#p134349


I've not used these boards myself before, but maybe others here have. Good luck

 

[Lime]

The description given and method suggested is to protect the internal living conditions from damp.
What about the house structure particularly the wood?
The damp needs to be kept out of the wood as much as possible.
Woodworm is a symptom of dampness.
Woodworm require the wood to be damp and will die off in dry timber.
Sealing the wood frame into an already damp environment will make the damp, rot and woodworm problem worse.
A waterproof barrier on the inside surface of a wall is always going to cause the damp to build up in the structure of the wall unless the wall exterior is ventilated well so that evaporation can take place.
It is far better to minimise the amount of water getting into the wall structure in the first place and essential to have ventilation/evaporation.

Old houses were not designed to contain very warm, moist air when outside conditions were cold.
Therefore heating an old house must always include ventilation to expel the moisture held in the warm air.
Unfortunately the modern desire to use less fuel and to improve insulation does not make good ventilation easy or without cost.
the process of installing insulation into a building, old or new, is a mixed blessing for the structure of the house.
Condensation is more likely to occur in hidden places and can be trapped.
New build design uses a waterproof barrier in all the exterior structure to prevent water getting in but living in a fug of damp warm air creates ideal conditions for condensation.
Old build design expected water to enter the exterior structure and relied on evaporation both inside and out to keep the dwelling nearly dry.
If the evaporation is prevented the problems mount up.
Modern solutions are not always the best in these circumstances.

The question I'd ask about the system proposed is what ventilation, if any, will occur in the 25ml gap?
If the answer is none, I'd be worried.

 

[MatthewC]

I'm surprised that your house isn't listed as I think I read somewhere that all houses built before 1700 were listed, plus "most" 18th C houses. Can anyone provide any illumination on this requirement please?

 

[Flyfisher]

I used to also believe that was the case, although I can't remember my original source. But from the personal experiences of some PPUK members it would appear not to be so.

 

[FamilyWiggs]

I used to also believe that was the case, although I can't remember my original source. But from the personal experiences of some PPUK members it would appear not to be so.

Ours was built before 1700 and is not listed. In terms of architectural merit I think it has enough - fireplaces, beams and some nice original wattle and daub panels to warrant it. But I could be wrong. I certainly won't think about it for now though.

 

[skier-hughes]

Ours was built around 1400 and is not listed. Our Co said that in the 80's when they had a big listing programme people drove round, looked at the outside adn decided that way if it was worth persuing, ours doesn't look too interesting from outside, aluminium d/g concrete roof tiles, but when the co came inside he was saying we were one of only 2 in staffs to have this, one of only 3 to have that and said he'd prefer our house to be listed, but nothing's happened since.......

 

[Moo]

Perhaps the CO is waiting until the aluminium d-g and the concrete roof tiles have been replaced before pursuing the listing?
I seem to remember reading somewhere that listing applies to the house in its entirety, and all sorts of horrors have to be left in place in perpetuity.

 

[Penners]

I'm surprised that your house isn't listed as I think I read somewhere that all houses built before 1700 were listed, plus "most" 18th C houses. Can anyone provide any illumination on this requirement please?

I suspect that there's a significant number that are not listed, simply because (as Graham has explained above) their age and architectural value wasn't apparent to the inspectors who checked them out (briefly) from the roadside.

 

[FamilyWiggs]

They'd have trouble doing a drive-by out/up here!

(This is much more comforting to think, than following a detailed inspection it wasn't considered worthy )

Mind you for the past 30 years it's been tanked and plasterboarded to within an inch of its life with fake beams covering the...er...beams :roll: and fake stone covering the...er....stone fireplace! Slowly the house is revealing itself to the world again.

 

[HelenS]

Thanks for your replies, I work silly shifts so have not been able to respond before, here goes

CR - interesting link, I may give the company a call to discuss these boards further, may be somone else has used them too?

Listed status - we are definately not listed but does appear on a map from 1646, our neighbour lives in a farmhouse and that is also on the map. (he showed us the map) We believe that the original house was timber framed with large pink sandstone boulders at the bottom, and was quite small, it had later Georgian and Victorian additions. Some bright spark then obviously decided to roughcast render it to hide all the different types of brick work and make it look like one large house. The render is several inches thick in places and in one area, under several rough layers, is a smooth finish made to look like large square stones, that reminds me of the houses in Leamington Spa. Next week I'll take some pics of whats lurking underneath and post them, if anyone is interested.

Lime - the more I research about the best ways to do things the more I become confused. There is so much contradictory advice out there. I think I've got it sorted then something else gets thrown in the pot. The house will eventually have the render removed and then I'm hoping that this will let it breath, so possibly the 25mm air gap will be useful, or do I need to put some kind of air brick into the outside wall? The two outside walls only have 2 wooden beams in them as they are part of the additions to the original build. The walls are not wet or damp and we have removed all of the woodworm ridden floor boards, just the huge joists left. There are the original upright beams in one wall and sadly the wood is not in good condition and very wood worm eaten and the lath and plaster between the beams is in a very sorry state. The room has been airing for about 6 months. Would it be best not to have an air gap and no type of membrane and put the sheeps wool directly onto the brick outside wall with my wall board on top of that?

My husband and I have booked onto a seminar in Bristol on 30th October entitled "Understanding Traditional Buildings" , presented by Mike Wye. We are very keen to learn as much as we can to do this house justice. At the moment she's a bit like me. Looks ok on the outside but the interior structutre needs an up-lift!!!

 

[MatthewC]

Hi Helen

You're definitely in the right place for lots of advice on lime etc - I'm a relative beginner but I would say that if your render is lime based, then it doesn't have to come off as it does allow the walls to breathe.

I did a lime course with Mike Wye last year - you'll enjoy what he has to say on the subject. I suggest that you write out a list of your questions/issues and cross them off as he answers them in his talk, as you might be in information overload!