Survey results - talk to me about damp, cavity wall insulation, wall ties and more!

[TheElementsSong]

We've received the survey report on the 1920s house we're buying, and there are quite a few 3's. Many of them don't really worry me, as we're used to living in older houses (Victorian/Edwardian), but there are a few things that I don't have experience of and would appreciate comments from you knowledgeable folk.

The survey found high damp meter readings (I know, I know, just bear with me!) in various places, of which I am only concerned about two of the external walls - we had noticed at least one area of possibly blistered paint internally when we viewed. The surveyor says: "The walls are of cavity construction... appear to have had cavity wall insulation installed... Externally on the flank wall, we also noted efflorescence on the surface of the brickwork indicating that this area of wall is damp." He then adds that it is not clear what the cause is, and this is what worries me. I'm sure I've read that cavity wall insulation can cause damp - is this true, and is it expensive to put right?

Also, what are wall ties? "In a number of areas on the external walls, there are hairline horizontal cracks in the bed joints of the brickwork. This seems to be an early indication of corrosion of the original metal wall ties ..." Could this be related to the damp?

Re: the wall ties, they are metal ties that link the two leaves of the cavity wall together. If they are corroding, then they are likely to fail in time, and will be as a result of damp.

Is the finish externally brick, or a rendered finish? How many locations was damp found?

Thanks orangina, that's very helpful! It's all brick externally.

There's one particular flank wall which appears to be damp (in two ground floor rooms) and then another damp area on a rear wall.

There was also damp in a chimneybreast, but I understand that because it's not in use and needs a vent.

What is the pointing like on the external brickwork? That can be a source of water ingress. You need to know WHY it is damp, otherwise you can't hope to solve it (and generally, you do need to solve damp.....)

Nothing was mentioned about the pointing in this regard, which I assume means it is OK.

CWI does not exactly cause damp, but sometimes, if there is a source of damp making the wall wet, it can obstruct drying-out. The installer is supposed to identify such causes, and until/unless they are rectified, is not supposed to install CWI. If they break this rule, they can sometimes be forced to remove it. If you order it through BG or one of the other utility companies (often free or subsidised) they are very anxious to avoid such cost, so are particular about inspecting the walls before agreeing to do the work.

If you scratch the pointing with your thumbnail and it crumbles, it needs re-doing. You will probably see it has eroded if you look.

Usually wet walls are due to rain penetration, spilling gutters and leaky downpipes, loose render and bad pointing. In some areas there may be persistent driving rain so often that the wall does not have time to dry out.

CWI does not, as some people think, cause condensation. By making the inside surface of the wall warmer, it causes the inside surface to dry out, and reduce condensation occurring on the inside surface of the wall. If the house is damp for some other reason, this means that more of the condensation occurs on the windows where it is more noticeable.

If the brick is exposed, you can sometimes detect wet brickwork by eye, as it is darker, and this gives clues to its source.

Removing rusty wall ties, and replacing with new plastic or stainless, is fairly easy, but you will have to pay for scaffolding. It is a common job, and if your house needs it, lots of other local houses of similar age will need it too, or will have had it done, so there should be local builders and contractors familiar with the job.

Yippee, PigletJohn is here! I hope the CWI was installed by somebody reputable - will of course be chasing for paperwork through our solicitor. I guess the nightmare scenario is that it's been put in by a dodgy installer and will have to be removed but I'll keep my fingers crossed! Unfortunately we're a bit far away and can't go to the house to scratch the pointing, so I can only go on the (lack of) comment in the survey. I'd hope he was on the look-out for such things, as we'd flagged the blistered paint (internally) to him in advance. I think our plan for Monday will be to (a) phone surveyor to ask for more details; then (b) book an independent damp surveyor.

Thanks for reassuring about the wall ties too, I'm getting the impression then that it won't be too expensive to sort? It's just all adding up though, I didn't mention the other 3's in the survey including the roof being in a poor state and needing to be replaced , so we will also need to find someone to quote for that.

I'm not sure whether to try renegotiating with the vendor, as the valuation was for the agreed price "provided that you are prepared to accept the cost and inconvenience of dealing with the various repair/improvement works".

Do not invite into your home anyone who sells damp-proofing, because they will advise you to buy damp-proofing.

An experienced local builder will often recognise where the water is coming from, and know how to repair the defect.

Post photos when you can.

We live in a 1930's house and have two cavity walls. I spoke to British Gas about insulation and they said (re cavity wall insulation) that if it becomes wet due to a crack in the wall etc, then it can keep the moisture in the wall making it very hard to dry out and therefore actually get rid of the damp.

We have decided to leave our walls and not get it put in, but my Mum's old house had it and never had issues in the twenty years we were there.

Depends how much money is in the kitty as to whether the vendor will negotiate or you can fund everything that needs doing. Our house was very good on paper, only threes were electricity and heating/water. We are getting cracks in the render patched up, few slipped roof tiles put back, gutters patched up and sorted and it soon adds up :(

I fear the vendors will not be very open to negotiation but I guess we'll have to see.

We are not big fans of damp-proofing salesmen so we will definitely be looking for an independent surveyor (any recommendations gratefully received!).

Update: Received the specialist damp/timber/wall tie survey and it is not good reading .

The wall ties are indeed rusted and will need replacing (approx £4K). There are areas of poor pointing on all elevations, plus stuff (CWI probably, but could be other rubble) in the cavities, which seems to be drawing moisture into the inner leaf - therefore some/all of the pointing needs to be redone. The gutters all need replacing. The external ground level is too high (too close to the DPC) and should be lowered. Plus a bunch of other stuff. Altogether it looks like, conservatively, over £10K of work .

Can't decide whether to renegotiate with the vendor (who would probably rather burn down the house than concede another £10K) or give up on the house.

if you want the place, ask for £15k off given all this work. They will say either yes or no.

but this is what surveys are for!

Drafting email to agent now. Feeling rather down and wondering if we should just pull out.

if in doubt.... run like hell!

I know you've spent cash on the survey and other stuff - but this is why you do it.

also just re-read and note the shonky roof. You can always raise further queries with the surveyor, he works for you.

Email sent, so now it's just a waiting game to see how the vendor responds.

But yes, basically we had been willing to "swallow" the cost of replacing the elderly roof but on the basis that any other problems were relatively minor. Now we've been rattled at the idea that the house has simply not had any basic maintenance done and is just going to end up a Moneypit.

I've been looking on Rightmove at other houses already