Damp proofing a house - cost

[ClareCottage]

We need this info urgently and can’t get someone out to give us a quote for two weeks.

What is a ballpark figure on damp proofing a 5 bedroom semi-detached house approx 2000sq ft? Location: London.

Has anyone had it done and could say what they paid?

Thank you

Depends on the level of work you'll be doing I think?

We took ours back to brick and dug up the floors to install damp proof membrane underneath everything and vandex on the walls and thermal insulating plasterboard. This is not all that the work involved, a basic example. Expensive.

In another room, we hacked out a patch of damp plaster and replastered the patch, sprayed with waterproofing spray and stain blocker. Much cheaper.

My mums just had one large room done and was £2500

Is it an old house OP? If so have a read of this:

www.heritage-house.org/damp-and-condensation/managing-damp-in-old-buildings.html

1930s house - not sure if that counts as old.

Thanks for the replies so far. Any specific figures appreciated even if it’s not like for like.

I had no idea different types were even available so that’s helpful to know thank you. Are you able to share how much it cost you?

Definitely worth doing some reading before you commit to getting any work done. The house should already have a damp proof course. If you can work out where it is you might just need to put some air bricks in the external walls which will only cost a few hundred quid. Or maybe just lower the external ground near the house, again probably cheaper than getting ondljection damp proof put it.

If you can take some pictures then people on here might be able to work out where the damp proof course is.

Also worth knowing that injection damp proofs can cause issues in older houses as they can just end up meaning that the damp is trapped somewhere else.

Does it actually need a damp proof course?

Or do you have damp and are therefore thinking it is the solution because as posted above, it probably isn't.

A 1930’s house almost certainly has a working dpc already. Do you have wooden/suspended floors?
In any case, as others have said, it’s usually easier and cheaper to tackle the cause of the damp. Photos please!

It’s a house we’re trying to buy and the seller has refused to answer any qs about it/provide any paperwork

Seller quite probably knows nothing about whether it has a damp proof course or not. If house isn't damp it doesn't cross your mind.

I remember being asked these questions and honestly not having a clue.

Are you sure that there is an issue with damp?

And if there is you need to look at the causes:

• could be that the current owner is not ventilating/heating the house correctly
• there could be a leak somewhere (pipe, gutter,roof, bathroom...)

I have a 1930 house and there is a dpc.

I found a bit of mould in a couple of places but I cleaned it with a mould removing product and made sure that I ventilated and heated the house correctly. The mould never came back so it was due to the previous owners failing to keep their house correctly heated and ventilated...

Whatever you do get some advice from a surveyor first and don't trust companies that just want to inject expensive damp products into your walls...

In that case don’t buy it.

Have you had a survey done?

Have you had the results of your survey back yet?

Agree with others if it's not an easy spot yourself I'd recommend an independent damp survey (Vs ones that are looking to cross sell remedies e.g. rentokill etc). It's usually a specific thing that needs solving for or combination e.g. leaky gutter/roof/pipe, exterior ground is too high, not enough ventilation etc. Stay away from anyone suggesting injections

When we bought our 1930s semi the survey identified damp in the underfloor timbers. This was caused by the garden party being laid about the DPC. Idiots but easily enough rectified.

Yes we’ve had a survey. It’s pretty long and says some areas are unlikely to have a damp proof course and need one so we should ask for installation and guarantee document. In other areas he thought there might be one but it’s failing. Mostly found no damp around the house but some places came back with a high damp meter reading.

The seller has refused to provide any info or documentation so now we’re trying to get a quote which is proving difficult.

Don't do the injections, OP. Definitely read the link I gave you.

Damp meters are absolute bollocks.

https://www.heritage-house.org/damp-and-condensation/the-ping-prong-meter-guilty-of-fraud.html

There wasn't any damp in the house you are looking at so why would it need a damp proof course?

The survey identified potential areas damp could arise due to structural issues.

I honestly could not know less about this which is why I’m asking anyone/anywhere I can about this including here. My fear is buying a place that ends up costing a fortune to fix up the minute I walk through the door.

Thanks for those who’ve posted links, I’ll read over the weekend.

Did it say what the structural issues are?

Surveys are always written with a lot of arse covering with 'it might do this' 'I can predict that'

@ClareCottage “Yes we’ve had a survey. It’s pretty long and says some areas are unlikely to have a damp proof course and need one so we should ask for installation and guarantee document. In other areas he thought there might be one but it’s failing.”

So you want the vendor to get the dpc done? That won’t happen. The dpc companies only offer a guarantee if you get the walls tanked.
A 1930’s house will have a dpc, usually would be slate, occasionally bitumen. It’s possible the house has one, and they have extended the kitchen into an attached shed, that might not have had one. Unlikely though. They don’t fail, but local conditions make them ineffective, such as leaks, guttering, ground level, blocked air bricks.
Did you notice damp? A smell or marks on the walls? Do you have any photos from the advert you could upload?
In any case, you have a survey, you could ask for a few k off the back of that, but don’t expect too much if it’s in good condition and perfectly livable.

Also, if a dpc is missing, you cannot install one, only inject one, and that is not effective.

Surveys are always over cautious. You won't get money off for "some areas may need a damp proof course".

Part of the risk of owning a home is that parts of it will occasionally go wrong and need replacing or repairing. It's a bit like buying a second hand car. You can get all the surveys you need but something could still break and need fixing.

Can you post the bit of the survey about the damp? Then maybe someone who knows more can help interpret it?

Home buyers surveys are mostly just arse covering. If you think there might be an issue with damp then I would get an independent damp surveyor in.

Can you get a good general builder to go round with you and have a look? The damp proofing companies like Kenwood just want to flog you chemical damp proofing when often any issue can be fixed with some air bricks or clearing gutters.