Chemical Damp Course - is it worth the trouble??

[dave]

I'm pretty sure this topic has been done to death here, but I'd appreciate a bit of help...

On buying our 1900 end terrace house in August the Building Society insisted on a damp survey, which ended up recommending a chemical damp course in a few areas of the house, including two lengths of the party wall with next door (about 7 feet total).

The owners of next door, a large property management company, have been sods over granting permission under the Party Wall Act, and I've ended up getting all the work done except the bits on the party wall. I've had a letter from their surveyor over Christmas saying that we're now in dispute, that I ought to appoint a surveyor and that those two surveyors can go and select a third independent surveyor to adjudicate the whole thing, all at about £100 hour per surveyor. I get stuck with the bill for the whole lot, if it takes them 3 hours each to sort it out I end up with a bill for £1000 in fees to do maybe work costing maybe £80.

Anyway, having read around damp in Victorian houses a bit more while waiting for all this to be sorted out I'm wondering if I need it to be done at all, and I'd appreciate some advice either way.

When we bought the house in August it had been empty for about a year. The cellar is fairly damp and timbers have been replaced (in the past and by us). Several skirting boards have been rotten when they've been removed. When I took off the skirting board on one of the party wall sections the inside face of the board was wet with standing water and the timber plugs used to fix it to the wall were so rotten and wet that water could be squeezed out of them by hand.

So really, what I'm hoping someone can advise me on (difficult I know) is where to go with this. Is CDC a waste of time in Victorian houses, or will it be a good idea in these circumstances? Do I need more professinal advice and who from?

Thanks in advance

cheers

dave

[meow2222]

classic scam

that I'm afraid is the price of your inappropriate proposed works on what is 50% their property.

no

then you have a serious damp problem to sort out. A chemical DPC wont have made much difference.

waste

[John Anderton]

I'm no fan of chemical DPC nor of people/companies being bloody awkward so, in your position, I'd be tempted to write back to the company and tell them you've called off the works.

Then I'd take a wander around the garden looking for drainage problems,

Cheers,

John

[Chris Bacon]

Mmm, interesting...

You've got a cellar... have they, too? You have an end-of-terrace house.. where was the other remedial work specified? Where on the wall is the damp (cellar floor level, ground floor level)? Can you do a quick ASCII pic., or upload pictures to some site for perusal? A bit more info. would be very useful.

[The Natural Philosopher]

I bought a house that HAD been injected.

Timber frame on brick plinth. There was evidence of structural rot.

NOW waht tramnspoired was interesting.

The outsid walls solid double skin brock under te sole plates, which were injected well, did not have any more damp problesm, but te inside walls running across teh building, did. One had a kichen built on teyh other sde, and it semed one patch go missed somehow.,. Ther was asmall patch orf risingh dampo there. But the absolutely dire problem, which I never cured, was around te brick fireplavce. This was too big to inject, and all te palster and woodwork around there ended up sopping wet after a storm. I thought it ws coming d9own tey chimney, but it wasn;t.

When I demolished the whole house there was a lake under that floor.

My conclusion is that chemical DPC, done properly really does work.

However, it may not always be possible to do it properly, and, in the case of my hoise, what might have been as effective would have been to dig a french drain around it to lower the water table, and keep the underfloor space dry. And then use ventialtion and heating to control the damp.

[meow2222]

Sounds like an unusual case, and it sounds like you did have genuine rising damp. The OP etc should realise that >99.9% cases diagnosed as rising damp are in fact not rising damp. RD exists but is rare. Nearly all cases turn out, on _proper_ investigation, to be either condensation or penetration. Sticking a damp meter into walls and hoping for work doesnt even begin to be proper investigation.

NT

[manatbandq]

I think some of it got into your keyboard.

MBQ

[Mark]

You will never get the definitive answer to this anywhere. FWIW my answer is no If you are also having problems with next door PW act, I would recommend this

does work is far less destructive to the house and has no long term replacement problems. Which even _IF_ CDP is done correctly, only has a life expectancy of 15 ish years.

-

[jim_in_sussex]

scam alarm sounds!

most chemical DPCs are water based & hence initially make the wall even wetter.

consider using Dryzone which is not water based and is a cream which disolves into the wall over a few weeks.

see

is based in Horsham, Sussex: plenty of info on damp walls on their web site. Highly recommend you review the info, even if you don't go down the Dryzone route.

I used Dryzone on a damp (but not dripping wet) wall about a year ago & it seems to have worked.

HTH

[meow2222]

swapping one scam for another wont solve the OPs problem.

NT

[jim_in_sussex]

Interesting.

I have used several methods of damp proofing.

Whilst I would agree that the only 100% foolproof method is an inserted dpc barrier, Dryzone does appear to give good results for a mildly damp wall. Are you saying it doesn't work?

By comparison, IMHE 'wet' chemical pressure insertion methods work only moderately well (although better than nothing): Dryzone is a lot less messy and doesn't leave the wall damper than it was when you started.

[Phil Addison]

We are not great believers in chemical damp treatment here for various reasons. Google the group for more, but it can work in some circumstances, However before you even consider remediation you must determine the source of the damp. Rectification varies greatly according to the source of the wet. Anyone who just says "its damp, you need our XYZ treatment" is a cowboy (and most damp treatment companies are).

Give us a lot more detail of the property construction, symptoms and especially what is outside the house. Can you see the damp proof course outside or is it buried? What is under the floors. What is the cellar like?

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[meow2222]

What I mean is that damp proofing chemicals are not imho a good solution in most cases of damp, whether water based or not. Usually the right solution is to locate and resolve the cause of the damp. When that proves impossible, encouraging evaporation tends to be a good approach. Sealants/waterproofers/chemical dpcs do the opposite of course, sometimes making the wall waterlogged. Which is not always bad, but often is.

NT

[Phil Addison]

I agree with that but it should be pointed out that injected damp proof courses are very dependent on the material they are injected into. In a good material they work (given that you do have an inherent damp problem, not something else like a bridged DPC), but in an unsuitable wall, say with a rubble core, or many cracked bricks etc, it is useless.

More details here

DPC cowboys don't know (or care about) this.

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[Phil Addison]

Not the white spirit based chemicals. It does stink for several days after application though.

Interesting. I had a look at the Dryzone site and they talk a lot of sense. I was quite impressed with their document "RISING DAMP AND ITS CONTROL"

starts off well with "Rising damp is not the most common form of dampness encountered in buildings; this is left to condensation. However, it is very likely that a high proportion of older buildings are affected by rising damp to some degree or another, and it does cause problems with positive identification, appropriate remedial action and ancillary works."

Interestingly they concentrate on damp proofing the mortar rather than the brickwork, since the mortar separates each course of bricks, and if waterproof will block the damp. That sounds very plausible to me.

They also address the rubble wall problem, though not rigourously enough IMO.

Shame they don't actually explain how the cream migrates and cures.

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[Phil Addison]

There is nothing wrong with the materials sold for this damp proofing, only in their misuse.

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[meow2222]

or tell the truth about rising damp, that less than 1% of damp cases are rising. The main causes are condensation and penetration from high ground levels. Thus making the use of DPCs usually ineffective.

NT

[Chris Bacon]

"What they said".

I'll have a look at their rising_damp_book.pdf when I've a mo.

[Phil Addison]

A case of reading what you thought it said perhaps?

Phil

[Chris Bacon]

Looks pretty good to me.