Damp - pull out or let vendor fix?

[schmalex]

We are trying to buy a newly built house, where our survey has shown up damp problems. The damp seems to be condensation (although why this should be when the house is unoccupied, I am not sure) and rising damp around a couple of fireplaces. There is a lot of moisture inside the house, causing black mould in places and making the windows hard to open/shut throughout.

It is a one off house on an existing road, not on a new development.

We are a hair's breadth away from pulling out, but the vendor has now seen the survey and said they will put everything right and would like to chat with us to allay our fears.

I'm not really sure what they can say to convince me that it can be fixed. Has anyone any experience with damp being successfully cured? Conversely, has anyone had a nightmare with it where various treatments didn't work?

We have had to exchange on our sale and will be moving into a rented house in a couple of weeks. So in theory, even if it took a couple of months to sort out, it wouldn't make much difference to us as we're no longer in a rush to move in.

But to complicate things, we had a close second choice house (not new) that is still on the market and I am tempted to just write this one off as a bad job and start from scratch by putting an offer in on that one.

There are not many houses on the market where we are looking, and people seem to stay in family houses a long time.

WWYD?

Why would they need to see the report if it's rising damp (you can see on walls and easy to id because it only goes up so far then gravity takes over). Why would they also not ventilate while house on market and let it get this bad? Did the house have no heat at all as it got colder?

if there is a lot of damp in an unoccupied house, I think there is probably a water leak. If the house is 50 years old or more it might be the water supply pipe. If it is buried under a concrete floor it will be a pig of a job. If you are really lucky it will be the sink, or a radiator pipe.
The windows will be wet near the source.

Or it might be that some buffoon has laid a path or patio against the house, blocking airbricks or allowing puddles against the wall. If so it will have to be dug up.

Disused chimneys need to be ventilated top and bottom. An airbrick will do.

Chemical injected DPCs do not cure leaks.

revision

You say it is newly built. Mortar, concrete and plaster are all made of water, with other ingredients. If it was raining during build, before the roof was on, all the brick, block and floors will be wet. It takes about a year for a wet house to dry, and it needs lots of ventilation. If it was my house I would have left the loft hatch open all summer for a good airflow, as well as all windows on trickle vent setting. Big builders' dehumidifiers can dry a house in about a month, at a cost of some £000s in electricity.

If the house is newly built (or very recently), is this sort of thing not covered in the NHBC or equivalent certificate?

New houses are meant to pass all sorts of tests for insulation and air-tightness but the corollary of this is that it can be hard for air to move around making them more likely to trap moisture. Perhaps this is what has happened, especially if it is unoccupied and therefore doors and windows aren't being opened to ventilate.

The rising damp would worry me more, tbh, as all new houses should be built with robust damp proof membranes. That would make me wonder how well it had been built. Although both forms of damp should be quite simple to cure, I'd be asking myself what else could go wrong. I'd definitely talk to the vendor (is s/he the developer?) but I'd also be considering the second house.

Thanks for your comments.

pigletjohn - it's a brand new house, built this year. There is a minor leak under the sink that showed up on the report, but would that really cause damp/mould throughout a 2300 sq ft house? Whenever I have seen surveys with damp mentioned before, it has been in a particular area of the house rather than high levels of moisture throughout.

Re digging up the concrete floors - this is the sort of thing I am dreading!

lalalonglegs - it may well be covered under the warranty, however even if we didn't have to pay for it, it could be a lot of hassle to fix. Hassle I don't really want with a toddler and new baby on the way. I need the vendor to put it right before we exchange.

Interesting about the drying out. Would new houses normally be dried with a dehumidifier before being sold? Has the builder cut corners here? I'm sure people buying new houses can't all be moving into mouldy ones.

The rising damp is also giving us concerns about how it has been built (and consequently what it would take to fix it).

The vendor is an individual who bought the land and had the house built for him, but he didn't build it himself.

a leak on a sink pipe can easily be half a bucket per day. Leave the house closed and unoccupied for weeks, that's a lot of water soaking into the floor, and yes, it will cause a lot of condensation.

A modern house should never have "rising damp" even if it exists.

Hmmm. But floor in kitchen is engineered wood so I would have thought that would have been damaged if lots of water was soaking into the floor.

The drying out stuff makes sense. I'm just not sure I want to live in a wet,
mouldy house for a year.

it depends if the wood flooring extends under the kitchen units. Many people don't. Water will then either soak into the concrete floor, or, if a suspended floor, will drip into the void. Either will make the whole house humid.

It's also possible that the story about the sink leak is not accurate. A radiator pipe leak can be a great nuisance if it is set in a concrete floor, or if it's under a tiled or boarded floor that the owners are reluctant to take up.

Thanks pigletjohn. It seems I am not being melodramatic when I worry it is going to be one big hassle...

I would be very cautious until I saw that the cause of the damp had been (1) accurately diagnosed and (2) fixed.

If he gets in big dehumidifiers, he might dry out the house but there could still be an unfixed fault

The whole point of a brand new house is to avoid hassle!! Definitely have a second look at second choice house! Did you not notice the damp smell when you viewed the first property?

I say put in an offer on your second choice house. If a newly built house already has major problems, run a mile.

There is a question as to whether rising damp actually exists.

It may well be drying out and as soon as you move in and heat it and ventilate it it will be fine, maybe condensation for the first winter and then dry.

Or it may be that there is fundamentally something in the way it has been built and it will become your nightmare home.

Personally I would pull out, breath a sigh of relief to a near miss and buy second choice.

I would pull out too. If it was summer you could ventilated, as we are going into Winter that wi be tricky and could damage your health.

Thanks folks - we have pulled out and will view our second choice house this weekend!
It's good to know I am not overreacting.