Victorian House with Cavity Walls ? Insulate

[lyndasfarne]

Hello to everyone, I am a newbie so I apologise if this question has been asked before.

Our house which is Circa 1883 has cavity walls and ties. We awere informed of the existence of the cavity walls by a Building Surveyor, before we moved in.

We have just had a leaflet posted by our local council offering free cavity wall insulation. I thought that I had heard somewhere that it was not recomended for Victorian houses, and would hate to do anything that could cause any damage.

I would be very grateful for advice/opinions.

 

[Moneypit]

Welcome Lyndasfarne

I would also be interested as our 1886 house has cavity walls too. Do you know what type of ties are in your wall? The ties in our walls are the same brick as the wall leaves, albeit that they are longer than the standard length bricks in the leaves. They are two leaf thicknesses plus the gap, which is 2 x 4.75" + 3.5", so 13"

 

[MdB]

This is second hand info from a friend of mine remembered from a while back...

The problem with old cavity walls is that the wall ties can rust / fail which leaves you with two single skin walls with nothing much between them. This is not good structurely and needs to be sorted if it is an issue. My mate lives in Southampton which has a lot of properties like this and having a camera survey of the ties is something that is done as standard during house sales. Fortunately, fixing the issue isn't that difficult I am told.

Injecting foam with good wall ties is something I can't see as being a particular problem but it is very much not something I would want doing if they are not. I would also want to see the insurance cover of the company doing the work though before they start.

edit - I have no idea if an 1883 wall tie would have been metal or brick. Hopefully the experts here would know. (Cavity walls didn't arrive in Cornwall until the 1970s if our house is anything to go by...) I guess if your brick is exposed, the brick pattern may tell you.

 

[stuart45]

A CWI company should do a survey of the property before filling the walls. If there are any problems such as poor pointing, dirty cavities, exposed walls, failed ties or narrow cavities they won't fill them.

 

[lyndasfarne]

Thanks for your replies

The wall ties which are visable are metal or more like iron. They seem in good condition, no erosion.

As it's the council offering to do the work I don't know at the moment which company they would use, obviously someone thay sub contact to, so how reputable they would be, we wouldn't know. That would not even be in our hands

I am just concerned whether it is worth it, as I had heard that the idea of cavity walls in Victorian property was to allow ventilation especially around the wall ties and surely filling would not allow any air space.

We obviously don't want to encourage any damp, so am dubious about having it done. It's all to do with their energy saving drive and I wonder if it's worth jepordizing for the sake of an improved EPC when we sell.

It's a little like if it's not broke, also wondered if the insulation makes a great deal of difference in warmth, have read that it doesn't in many cases.

 

[stuart45]

Even the experts can't agree on whether CWI is a good thing for any house, nether mind old ones. It has been known to cause problems although I know people who are delighted with the results. Apart from the ties the external skin receives less heat from inside, and in winter may suffer from the freeze/thaw issues and spalling of brickwork. I don't think anyone can give you a definite answer over the net. It is a lot a hassle to get taken out.

 

[Flyfisher]

We obviously don't want to encourage any damp, so am dubious about having it done. It's all to do with their energy saving drive and I wonder if it's worth jepordizing for the sake of an improved EPC when we sell.

I've no idea how good or bad CWI will be for your house but my feeling is that it has been happy (presumably) for over a century without it so, in the absence of proven expert opinion that its an unconditional good thing, I would tend to side with the "if it ain't broke" maxim.

If you're intending to sell in the near future then one possible downside, as you point out, might be a less-favourable EPC, but how much are you really risking? A few hundred pounds price reduction when you sell? (i.e. the cost of the new buyer installing CWI if they are really so concerned about it).

Another possible downside is that the CWI reduces ventilation within your wall and causes damp problems, wall-tie corrosion and will certainly prevent prospective buyers inspecting the internal condition of your cavitiy walls (which might be viewed as more of an issue than not having CWI). And the cost of putting any of those problems right will far exceed a few hundred pounds.

Hmm.

 

[MdB]

But then again, our heating costs are £500 per year compared to our neighbours £1500 - £2000. I hoping it will drop further too when we get the back of the house insulated as well.

 

[Flyfisher]

Fair point. If Lyndasfarne could find out similar info then it would certainly be valuable additional info to add to the decision pot.

 

[chuckey]

I insulated the cavities of my 1894 house with polystyrene beads about 28 years ago, no problems so far. I choose these as they do allow any water migration to drip down and the slight air flow also allows a certain amount of drying out, the downside is that their insulation properties are not as good as solid foam. Fibre fill is reputed to "pack down". The lads did a good job of filling and colour matching the holes, I have to look for them and I know roughly where they are!
Frank

 

[lyndasfarne]

Just wanted to thank everyone for their replies.

I spoke to the lady who was organising the survey and isulations. As we are under no obligation to take things up am going to have the survey done anyway. I feel confident that they will check carefully as I was told it depends on the size of the cavity, if there is a chance of any rubble inside etc. So I believe they won't even take it on if any doubts.

Thanks again.