Damp in old house

dont_use_vistaprint

I have an approximately 100 year old house, single brick detached no cavity, two chimney I working fire, good central heating. I’ve suspected damp for a while and after buying a moisture pin meter I’ve confirmed certain areas of the walls downstairs, up to our knee height are getting readings between 10 to 25%. Well, many areas are reading nothing or just one or 2% Visually there is practically no signs of damp other than one or two spots with a small amount of flaking paint and an internal structural wall where a small dark area has come through some painting a few centimetres above the skirting board but neither of these seem big problems,

have also had very light black mould appear in one corner of an upstairs bedroom, that was simply wiped off every couple of weeks, but after installing a dehumidifier airing and redecorating the bedroom has now stopped.



I was thinking of just stripping off the plaster downstairs on the bad parts and treating it myself.

But I I thought first  would get one of those free damp surveys done, obviously they are gonna try and sell you Services but I was interested to see what they claimed to find.


Below is what they have quoted for, they are saying the entire downstairs is suffering from rising damp through a defective /  simply aged DPC. That is the only root course analysis they’ve done it doesn’t seem to be any specific event causing this of them moisture coming up the walls of an old house.

there is also high moisture readings in the house, the double glazing is at least five years old and so none of it has the trickle vents and I think it’s fair to say there is poor ventilation generally in the house compared to modern standards. There is an existing PIV unit installed. That was there when I bought the property it is no longer working

they didn’t find any signs of damp upstairs or suggest any work done upstairs at all other than a PIV

Would you be inclined to get an independent damp survey, a paid for one, from a company that does not offer the remedial services?

my uncertainty is  I have no idea of the actual data from this free survey and I suspect they just want to sell you as much as they can and it might not all be required, but if there are genuine damp  issues not yet visible , I don’t want to leave them untreated. I guess many old houses or to a degree damp but at what point should you start doing remedial work?

29 meters DPC required - Inject cream resin internally and externally on 3 of 4 walls plus’s areas of two intern walls 

£4125

Chimney pointing and re-flashing 

£2450

Tanking & re-plastering of internal walls,  Lounge and dining room 

£1500

PIV unit  £2100

Total £10,175

Albermarle

There many threads on this subject on the forum. Most conclude that these treatments are an expensive waste of time.
If you have no obvious signs of damp, then probably best to do nothing except keep the house reasonably warm and ventilated. 
Additionally have a good look around outside for any issues that might be the source of damp, such as ground levels being too high/above the DPC, leaking gutters etc 

I have a approximately 100 year old house, single brick detached no cavity,

Just to avoid confusion, single brick normally refers to walls that are just the width of one brick. Really only suitable for non load bearing walls, such as low garden walls.
Your walls will be what is usually called solid brick walls, which are the length of one brick thick.

FreeBear

A DPC does not just "fail" - Think about it for a moment. It is sandwiched between a layer of bricks, so protected from UV damage. The brickwork would protect the DPC from impact damage too. Whilst building movement might cause some damage, it would be isolated sections, and not the entire length of the wall.

These "free" surveys are little more than a scam sales pitch for questionable "cures" that do not fix the underlying cause of the damp.

The proposed list of works contain just two that may be beneficial. Repair or replacement of the PIV system, although £2100 sounds well over the top for a £300-400 blower.

Repointing the chimney and replacing the flashing might be prudent depending on the current state. But you would be advised to use a pure lime mortar as it is much more forgiving with older buildings. Anyone turning up with a bag of cement needs a kick up the backside before removing from the property.

Injecting magic creams in to the walls will not cure "rising damp", and slapping a waterproof render/plaster (tanking) on the walls will just trap moisture in the walls. In 10-15 years, the problem will poke its head out further up the walls and you'll be back to square one. In the meantime, the moisture trapped in the wall will freeze during winter and cause the bricks on the outside to spall.

Instead of wasting money on questionable works, I'd suggest looking at the ground levels outside - This should be ~150mm below the level of the DPC. Any higher, and there is a good chance that splash back from rain is soaking in to the wall - Don't be tempted to use any waterproofing creams/paints on the walls as these will also trap moisture in the walls. Check your gutters & downpipes to make sure they are not overflowing..

twopenny

When a surveyor came to my 90yr old house there were some damp readings but he said they were what you would expect from an old house. 
Do you know what would be the norm for a house of that age? It would be worth finding out before you start.

If you have a corner with mould is it exterior? How long has it been like that? Is it a cold corner, blocked from heat by furniture?
Think what might be causing it before rushing in.

sheenas

The basic pin type meters are very easily confused and I would invest in a better meter for around £30. Further Roger has sone a number of damp related related youtubes vids. I have followed Roger for a few years now and a good egg. Try this one https://www.youtube.com/watch?v=k9LdpRvnHpA before wasting your money
 

spannerzone

Most damp proof experts are nothing of the sort and simply sales people with noisy 'damp' detectors to scare you into purchasing almost certainly pointless solutions. Damp meters are actually electrical resitance meters, if you have one, try gently probing your hand and it'll detect damp!

There are plenty of good guides online and in books to help resolve your issues....check for raised ground level outside, soil agaist a wall, poor external drainage, leaking roof, chimney, gutters etc. Don't dry clothes indoors, open windows when showering, get extrator fans for bathroom and kitchen..

I have a 100 year old end of terrace with 'Damp' and fitting bathroom extractor, kitchen extractor and a low cost Nuaire PIV in the loft and fitted myself and it  pretty much resolved the issues, the previous owner had done stupid things like using metal foil backed wallpaper which hides the problem for a bit but actually traps in the moisture.

Remember, your breathing will create a lot of moisture...without somewhere for it to go, it'll condense on your walls and windows.

dont_use_vistaprint

Albermarle said:

There many threads on this subject on the forum. Most conclude that these treatments are an expensive waste of time.
If you have no obvious signs of damp, then probably best to do nothing except keep the house reasonably warm and ventilated. 
Additionally have a good look around outside for any issues that might be the source of damp, such as ground levels being too high/above the DPC, leaking gutters etc 

I have a approximately 100 year old house, single brick detached no cavity,

Just to avoid confusion, single brick normally refers to walls that are just the width of one brick. Really only suitable for non load bearing walls, such as low garden walls.
Your walls will be what is usually called solid brick walls, which are the length of one brick thick.

Thanks for your reply very helpful. There is one potential air at the back where decking is higher than the damp proof course which I can look to resolve or protect the wall from rain bouncing against it but other than this there is no obvious signs or causes of the damp  and in particular one of the internal walls that has a damp patch so my conclusion and what seem to be the surveyors conclusion is it is just age and ineffective existing DPC - do you think that’s a reasonable conclusion ?

dont_use_vistaprint

twopenny said:

When a surveyor came to my 90yr old house there were some damp readings but he said they were what you would expect from an old house. 
Do you know what would be the norm for a house of that age? It would be worth finding out before you start.

If you have a corner with mould is it exterior? How long has it been like that? Is it a cold corner, blocked from heat by furniture?
Think what might be causing it before rushing in.

Yes I think the thin layer of black mould on the internal bedroom corner, north facing wall was caused by cold , lack of central heating (when gas prices with sky high !) and lack of ventilation. This seems to have been resolved now and seems completely unrelated to the other issues downstairs. 

I’ve done quite a bit of research on what moisture levels are normal for old houses and some of mine do seem to be above that.

there is a small patch in the corner of the downstairs lounge on an internal wall that is reading between 20 and 26% moisture 12 to 18 inches high.

another internal wall between the lounge and the stairs is reading around 10% at the same height which I believe is within expected readings for house this old but was one of the walls the surveyor wanted to treat.

other than where the decking breach is the DPC at the back. My external walls seem to be reading no more than around 2.5 to 5%.

either side of the French windows where the decking breaches  the DPC, I get readings of 7-12% and there is some signs of blistering  paint

Another  internal wall between the dining room and kitchen has readings import as high as 30%  and the paint is a slightly different colour to around knee height, whilst the other side of this wall in the kitchen is reading only 5 to 10%

dont_use_vistaprint

FreeBear said:

A DPC does not just "fail" - Think about it for a moment. It is sandwiched between a layer of bricks, so protected from UV damage. The brickwork would protect the DPC from impact damage too. Whilst building movement might cause some damage, it would be isolated sections, and not the entire length of the wall.

These "free" surveys are little more than a scam sales pitch for questionable "cures" that do not fix the underlying cause of the damp.

The proposed list of works contain just two that may be beneficial. Repair or replacement of the PIV system, although £2100 sounds well over the top for a £300-400 blower.

Repointing the chimney and replacing the flashing might be prudent depending on the current state. But you would be advised to use a pure lime mortar as it is much more forgiving with older buildings. Anyone turning up with a bag of cement needs a kick up the backside before removing from the property.

Injecting magic creams in to the walls will not cure "rising damp", and slapping a waterproof render/plaster (tanking) on the walls will just trap moisture in the walls. In 10-15 years, the problem will poke its head out further up the walls and you'll be back to square one. In the meantime, the moisture trapped in the wall will freeze during winter and cause the bricks on the outside to spall.

Instead of wasting money on questionable works, I'd suggest looking at the ground levels outside - This should be ~150mm below the level of the DPC. Any higher, and there is a good chance that splash back from rain is soaking in to the wall - Don't be tempted to use any waterproofing creams/paints on the walls as these will also trap moisture in the walls. Check your gutters & downpipes to make sure they are not overflowing..

my main concerns are the internal walls that are clearly damp 20 to 30% with visible patches. What would you recommend to do for this?

dont_use_vistaprint

FreeBear said:

Injecting magic creams in to the walls will not cure "rising damp", and slapping a waterproof render/plaster (tanking) on the walls will just trap moisture in the walls. In 10-15 years, the problem will poke its head out further up the walls and you'll be back to square one. 

Then why are these solutions certified by all the relevant bodies and the same? Solutions recommended when you get independent homebuyer for surveys if the injectable resins , removing plaster , tanking re applying waterproof plaster - if these do not work then why are they accepted by surveyors and mortgage providers as the solutions and if these aren’t the solutions then what are the solutions for internal walls where there is no external events causing damp? It is simply moisture in the ground and an old building

FreeBear

dont_use_vistaprint said:

FreeBear said:

Injecting magic creams in to the walls will not cure "rising damp", and slapping a waterproof render/plaster (tanking) on the walls will just trap moisture in the walls. In 10-15 years, the problem will poke its head out further up the walls and you'll be back to square one. 

Then why are these solutions certified by all the relevant bodies and the same? Solutions recommended when you get independent homebuyer for surveys if the injectable resins , removing plaster , tanking re applying waterproof plaster - if these do not work then why are they accepted by surveyors and mortgage providers as the solutions and if these aren’t the solutions then what are the solutions for internal walls where there is no external events causing damp? It is simply moisture in the ground and an old building

You pay enough money to the BBA, they will certify anything.

The PCA is a trade body promoting all the bad & dodgy products such as spray foam insulation & damp treatments - They have a vested interest in these products. Due to advertising and lobbying behind the scenes, they have positioned themselves as "experts" and have cosied up with mortgage providers. Bear in mind that you don't need any real qualifications to become PCA accredited unlike a chartered RICS surveyor (degree level training).

If you have damp on an internal wall, it is likely to be a leaking pipe. Or if close to a chimney, poor flashing and/or rain entering an open pot. But don't discount damage to an external wall - Had a crack in an external wall here about 3m above ground level. When it rained heavily, water would drip through a ceiling some 2m away adjacent to a flat roof. Spent quite a bit of time & money "fixing" the flat roof & adding extra flashing. It was only after the crack was pointed out (and repaired) that the leak was fixed.