How do I know if I can trust my damp surveyor?

Arghbloodyhouse

I recently bought my first home and came across some damp. The building surveyor I got during the buying process made a vague reference to penetrating damp on the ground floor that had not caused any visual patches to form but on taking to him I got the impression this was just expected for a house of its age (140 years).

The damp I've found is on an internal party wall in the kitchen. I optimistically thought it might be condensation as it is next to the cellar door, so the coldest part of the room. 

The specialist damp surveyor I got round says it's rising damp and that it extends from the external wall (to of the cellar steps, about 1m away from the noticeable patch), through the kitchen, into the living room and has begun to affect another internal wall.

Everything I read on the Internet suggests rising damp is rare,and that its often misdiagnosed, and that modern techniques of damp proofing can worsen the problem in older houses.
This makes me wonder whether I can trust the damp survey and knowing nothing about these things I'm not sure what to do. Is there any way I could check if rising damp is actually likely? 

Doozergirl

Do they want to hack all your plaster off to the magic height of one metre, inject a water based chemical damp proof course and then cover it all
with a plaster containing a specialist waterproofing agent, or similar? 

Have they suggested where this excess
water might be coming from or is 'rising damp' a good enough reason for them? 

Were they free or did they charge an unfeasibly low rate for someone genuinely earning a living as a qualified surveyor?  

If any of the above is true, I would not trust them.  They are a salesperson.  They may even believe what they are saying. 

"Rising Damp" is not a diagnosis of a specific issue.  Old
houses do get damp in places, and the way to sort it is find the cause and prevent it from happening.  It could be condensation near the cellar - perhaps the cellar isn't ventilated correctly and has high humidity that is trying to escape into the house, it could be that the walls have gypsum plaster and can't breathe correctly and so lime plaster would help it breathe. 

The fix could be really cheap. What you want is a surveyor who is independent and does not sell chemical damp proofing products, but understands old
buildings instead.  They won't be cheap, but they will genuinely teach you about your house.
 

Arghbloodyhouse

Doozergirl said:

Do they want to hack all your plaster off to the magic height of one metre, inject a water based chemical damp proof course and then cover it all
with a plaster containing a specialist waterproofing agent, or similar? 

Yes.

Have they suggested where this excess
water might be coming from

Nope

Were they free or did they charge an unfeasibly low rate for someone genuinely earning a living as a qualified surveyor?

About £100 to get him to take a look a it - they're a Which? Magazine "trusted" trader.

That said, I'm yet to receive their written report, so I will wait until I've read that to see what I think. Once he'd left and I really thought about it, I couldn't quite work out where the damp was 'rising' from. You'd need to go 7ft down from the damp patch before you hit earth; he seemed to suggest the damp was travelling horizontally rather than vertically (although the house is on a hill so gravity would do that!), so perhaps he felt the damp was coming from the side of the house; but if that's true why has it reached a height of around 4ft up the wall at the cellar steps and then 2ft up the wall in the kitchen?

I definitely need to understand all this before I take action. Just feels like such a minefield!

Doozergirl

Do you want to post a photo of what you can see?    

Are there no problems on the outside walls at all? 

FreeBear

Arghbloodyhouse said: About £100 to get him to take a look a it - they're a Which? Magazine "trusted" trader.

Which company was he from ?

I'm guessing a PCA member - The PCA is the trade body for the damp proofing industry, and their training & qualifications leave much to be desired.

 The methods they generally use to detect damp (pointy meter with flashing lights poked in to a wall) are heavily skewed by the type of surface and salt content to the point of being meaningless - The meters can only be relied upon to give an indication of damp in untreated wood, not plaster, brick, or any other building material. That said, in the right hands with a modicum of knowledge, they can be used to identify a problem area but not give a definitive diagnosis.

For £100, you have been had.

Arghbloodyhouse

Doozergirl said:

Do you want to post a photo of what you can see?

Thanks!    
This is the area where damp has come through the paint work (paint job around 2 months old so came through quick!)

Close up of the top of that patch Close up of another part towards the top  Efforescence about 4ft up the wall at the top of the cellar stairs Bottom of patch in kitchen  Crumbling plaster at the top of the cellar stairs

Are there no problems on the outside walls at all? 

He couldn't find any and neither could I. He said the external wall had been 'tanked'(?) Just got the report through and he describes the waterproofing as: "Above the ground level, a render plinth could be seen along the base of the left hand gable and it is likely that this continues below the visible surface, forming part of the waterproofing system."

Arghbloodyhouse

FreeBear said:

Arghbloodyhouse said: About £100 to get him to take a look a it - they're a Which? Magazine "trusted" trader.

Which company was he from ?

I'm guessing a PCA member - The PCA is the trade body for the damp proofing industry, and their training & qualifications leave much to be desired.

I'd rather not say which company right now in case he's actually bang on right and I just haven't understood it yet, but yes they're a PCA member. I called them up when I got the report to ask questions, one being alternatives to the chemical injection because I was warned by the initial general property surveyor not to use chemical injection in this house because it's not suitable for this type of construction. They don't do other types of damp proofing, only chemical injections, so I'm not massively comfortable going with them anyway.

Doozergirl

A render plinth is the opposite of helpful. It allows water to bridge the original damp proof course. 🤦🏼‍♀️  If we didn't already have answer about this guy, we do now.  

Walls in the middle of the house are pretty hard to diagnose, but I would be tempted to hack  back that gypsum plaster at the top of the stairs and give the wall a chance to breather for a start. 

Is the cellar space directly under that room or are there any solid floors in the area?  It's so hard to guess when you don't know a house.  

Also, can you see plenty of daylight from your cellar?  Is it in its original condition or has it been treated/covered in some way? 

Can you post pics of the outside of the house?  With context please - so we can see the ground levels and the roof as well.  

Same for inside, it's the context that we need more than the close ups.  I should have said, sorry.  

Arghbloodyhouse

Is the cellar space directly under that room or are there any solid floors in the area?  It's so hard to guess when you don't know a house.  

Yes. Below is the floor plan (red lines being damp) that the surveyor did. The cellar lies below the kitchen only (the room on the left). The living room is straight onto solid ground. The living room floor is concrete (I've since had hardwood laid over that) and i believe the kitchen is concrete too - just looks like stone when I look up at the ceiling from the cellar.

There's no daylight from the cellar as it is really more of a coal hole - just a small damp space, no damper than you'd expect for a coal hole basically. It has what the surveyor has described as "waterproof slurry" and it has a drain on the floor for if he does flood (although so far despite floods in the local area there's been no problem).

This is how the surveyor described the cellar:

"There was found to be a cellar present beneath the kitchen section. This is a fairly typical unconverted space and there was heavy condensation formation on the steelwork at the front end and on the pipework entering the house at the front left corner. This was then dripping and causing some staining to the waterproofing slurry on the left hand wall. There was no puddling of water on the floor at the time of the survey however, should any ingress occur there is a gully to drain water away. We would not recommend any action being taken in this area."

I will go out and take pictures from the outside in a bit and get back to you. Thanks for all your help!

couriervanman

"they're a Which? Magazine "trusted" trader."

Doesn't mean anything

Arghbloodyhouse

Doozergirl said:

A render plinth is the opposite of helpful. It allows water to bridge the original damp proof course. 🤦🏼‍♀️  If we didn't already have answer about this guy, we do now.  

I should say, also. The render he's talking about runs along the left-hand side of the floorplan I posted - the wall on that side is not damp (above ground level, anyway).

The back wall is a party wall (it's a back-to-back property) that adjoins the neighbour's kitchen/living room/cellar.