Damp on recent survey/ problems with roof

[Sunflower960]

Hi,

I have received my report back from a survey completed on a house I'm purchasing.

It showed that the underlying to the roof needs replacing as defective and in some parts none at all.
Meter readings showed damp on both floors of the property, very high at the point of low ground floor.
I would imagine that the damp is likely coming from the defective roof as there is evidence of DPC injected on the external walls of the property.
I have 2 questions;
Does this require a whole new roof or isn't a simple job of replacing the underlying.

Once the root cause of the problem has been sorted, does more work to internal walls need completing or will fixing the problem eventually lead to the walls drying out.

Any advice would be appreciated. TYI 🙏

I’d beelined to look for another house. Problems with roof are expensive But there’s also problem with damp on low ground floor - most likely that has nothing to do with the roof. Most likely the Damp proof course is shot or the house doesn’t have a damp proof course. Very expensive to have new damp proof course. The reason we have surveys done is to highlight these kinds of issues. Personally I’d withdraw and look for another property. No one wants to live in a damp house or spend thousands getting it water tight.
Hope you find a good house

Hi there, @Sunflower960 - just to let you know that we've moved your thread over to our Property and DIY section. Hope that helps and best of luck with sorting everything.

Thanks.
I'm more thinking that if I find out what exact work needs doing I use this to have money knocked off the cost of the house.
Of course I'm still going to have to get this work done when/if I moved in.

I just don't understand enough to entirely know what work will need doing I.e. Just underlaying/if this isn't possible and would need new roof
If re plastering would need doing
If previous DPC has failed..

Thank you! 🙏

I wouldn't buy a house that needs a new roof or windows. Both expensive.

Sounds like the roofing felt is damaged or missing? Our roof doesn't have any felt and doesn't leak. If the tiles are fine then the roof shouldn't leak. Are there any tiles missing? Are the gutters fine? Is there evidence of leaks on the ceilings upstairs?

Injection damp proofs are crap and generally indicate that there is an ongoing damp issue that hasn't been fixed, just covered up. What is the external ground level like? Does the house smell damp? Is there signs of peeling paint or stains on the ground floor walls?

Also. How old is the house?

Damp at low level is usually caused by the ground outside being too high and bridging the damp course. It can often be fixed very easily by lowering the ground immediately adjacent to the house, eg by installing a French drain or similar. I had this done on my current house a few years back and it was about £600. Damp higher up on walls can be caused by leaking/faulty gulleys and rain pipes, which again, isn’t too expensive to fix.

You need professional advice though - what does your surveyor advise?

Yes the felt is missing and there are tiles on the roof that are being held in place with tingles.
No evidence of leaks in upstairs ceiling but damp meter shows damp on chimney breast. There are bulit in wardrobes to hard to see clearly.
I didn't see any damp at all in the house or smell anything when I viewed but one if thr meter readings are over 60.

No signs of anything when I viewed the house but I missed it.
The pictures sent from the surveyor shows a small amount of bubbling in the plaster. Damp meter readings here were 25.
I have asked for proof of warranty for the samp course and to see whn it was completed but I as far as I'm aware you should be removing the plaster and replacing when a damp course has been done which I don't know if it was.
I'm not completely clued up with these things

Around 80 years old

My surveyor advises I fix the roof and ask about the previous DPC to see if it has warranty.

There is damp on the ground floor living room at ground level with varying degrees including the chimney breast.
Damp upstairs on chimney breast.

I'm not entirely sure what to do here. I like this house but I want to be aware of the work that will need doing and consider asking it off the price

DPC certificates really aren’t worth the paper they’re written on. How does injecting a wall with a chemical in various spots stop water ingress? I say that without judgement - I got sucked in and had it done myself in a previous house.

Take a read of this: https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html

Damp on chimney breasts is often caused by inadequate ventilation (do the chimney breasts have ventilation grills on them? If not, they should be added) and/or by the way the chimney is capped at the top.

Definitely get a roofer round to give you an expert view on the roof, but the damp may not be as difficult to resolve as you fear. If you haven’t already, call the surveyor - they are usually far more candid on the phone than they will be on paper.

Disclaimer that I have no qualifications, just owner of Victorian terraced houses.

Sounds like two issues.

Fixing roof underlay means scaffolding up, they strip off the tiles/slates, strip off the battens, remove any remaining underlay. Then they apply new underlay, fit new battens, and then put the old tiles/slates back on replacing any that are missing or damaged. They'll usually redo the flashing too.

The damp needs a professional opinion from a damp specialist. A general building surveyor probably can't give you specific enough advice on this.

We pulled out of an old semi because of high levels of damp.

I had someone in to look at it and although he said it's not particularly expensive it's messy. It was rising damp so he said he'd have to knock the plaster off, inject with a chemical then re-plaster.

Out issue was there was water flowing down the drive into the air bricks.

We decided to walk away. I'm a severe asthmatic and I just didn't want the hassle or additional cost as this house was stretching us anyway.

Now buying a house that's 15 years old.

If the roof isn't leaking though, it isn't broken and doesn't need felting. Doesn't matter how the tiles are being held on as long a s they are doing their job and aren't at risk of falling off.

Damp meters are unreliable so you can ignore the readings from that.

The house will have had a damp proof course installed when it was built if it is 80 years old. It is more likely that it has been breached by something or there is a leak somewhere than that it has failed. Atripping the plaster off, tanking and replastering just traps the moisture in the wall rather than fixing the leak/ breach. Sometimes it can be as simple as fixing a leaky gutter or putting some air bricks in to improve underfloor ventilation. If you want to understand it more there is a good explaination on here. www.heritage-house.org/damp-and-condensation/managing-damp-in-old-buildings.html

Chimney may be an issue. Sorry but I don't know much about damp and chimneys.

Here’s a great example of what a con the chemical damp-proofing companies are. So PP’s issue is water flowing down the drive and in through air bricks. And the company’s advice to address that is hack plaster off the walls and inject a water-based chemical in to dry it out. Not to address the source of the moisture - that drive.

Sorry, this is a bit off-topic but it really really irks me, not least because a decade ago I was one of those getting one of the “free” damp surveys and then shelling out thousands on a completely meaningless “treatment”.

The heritage house website linked above is a really useful resource.

If the damp is on the upper part of the chimney breast that could be due to a chimney that needs repointing, lead flashing around chimney deterioration or ridge adjoining chimney in poor condition. Obviously if there's no felt, there's even less protection if there's no lining.

We've had many years of problems with our roof and bitten the bullet. The leaks were in our bathroom and bedroom upstairs near chimney (ridge needed re-doing, cement at bottom of chimney and flashing had it). Water marks down an upper central wall from the ridge. Water coming in down a valley into room at lower level. We have not had any damp at a lower level in the property, so I suspect there's something else going on.

If potential problems have been pointed out with the roof, it won't last forever. We've had three repairs in ten years and our roof had still had it. Cost us £10,750, we've got a converted dormer bungalow though, so scaffolding not too high and access could be gain off top of extension at the back.

@housemoveheadache it wasn't a 'company' he was actually an independent bloke and a friend of someone I work with.

I've asked him for an invoice for the hour he spent with us at the house, still waiting for it.

When pressed, he said it's fine.

Nice bloke. Sound advice.