Damp proofing!

[GreenEyedMonster2014]

Ok, so we have rising damp issues in the house we've just bought. We've managed to get 4 quotes. 3 of them have given quotes based on the DPC being inserted internally, meaning plaster removed, DPC injected and then replastering with damp fighting plaster (can't remember the technical name they've given). The other quote is a local contractor recommended by the agent who sold us the house. His quote is considerably cheaper for two reasons; firstly as far as I'm aware he's not a part of any association (e.g PCA), I'm not sure if that matters or not. The second reason is that he will insert the DPC from the exterior side of the walls, meaning no plaster needs to be removed. His reasoning behind this is that any surveyor will be able to clearly see that the house has had DPC without having to dig into walls etc. Obviously, I'm aware the damaged plaster will need redoing in due course but at least it means we can get it done on our own time.
My question to you is, does it matter which side of the wall it is injected? Does it also matter that this guy is not part of any association, so long as he can guarantee his work like the others?

The reason for removing internal plaster is that once a wall has become wet, salts can leach out of the brick / mortar into the plaster. These salts attract moisture from the air and in themselves cause damp. The only effective way to get rid of the salt is to remove and replace the plaster. It doesn't matter which side the DPC chemicals are injected from because they are only intended to temporarily mask the problem.

There's no such thing as rising damp. Most commonly it's penetrating damp caused by a leak in guttering or plumbing. Sometimes if the external ground level has been raised above the original damp proof course you can get some seepage, or if air bricks intended to ventilate a sub-floor void are blocked you can get condensation problems which appear a bit like what people imagine rising damp to look like. Especially in Victorian houses you will find repointing in cement and replastering with gypsum based products cause massive issues with condensation. In such cases people sometimes latch onto the completely made up concept of rising damp and end up paying thousands of pounds to a cowboy for pointless injection treatments.

Even some chartered property surveyors seem to have been taken in. I take it that your homebuyer's report mentioned rising damp.

Do not pay someone to vandalise your home by injecting chemicals into the masonry. It will just cause problems in the longer term.

Agree with Cheese.

What age is the house and where is the damp? Has the cause been diagnosed?

Apologies for the late reply, we've been busy moving into the property and trying to sort the mess out.
We've had four separate specialists come in and say pretty much the same thing, that either DPC or tanking is needed on all exterior walls. There are other factors that are causing damp which also need to be addressed such as chimney flashing, a leaky boiler pipe and faulty guttering, single glazing in need of replacing and no proper ventilation in bathroom and kitchen. We're saving up to work on all these things before the winter hits. I'm still in two minds about the DPC but I agree that the damaged plaster will need replacing.
I think whats annoying me the most is that most are saying once DPC is done, you have to wait for 9-18months to dry out the brick before you can decorate. This house is a mess and we've just found out I'm expecting, so I really need the house to be done before the baby comes.

OliviaBenson the house was built 1890. The previous owners have had it since mid 60's and they have not looked after the property at all.
Also, we do need to lower the floor level outside and sort out the french drains as they are not wide enough

It sounds as though you have enough sources of damp between the external drainage, poor ventilation, leaky pipes and leaky flashing that it would be absolutely impossible to diagnose other sources of damp accurately. Each of these four specialists probably just poked the walls with a damp meter and got a beep. They will have no way of knowing where the damp came from just by knowing it's there.

Were these independent specialists? As in, were they from companies which offer damp treatments? Did you pay them or were they sales free consultations?

The sensible thing to do is to sort out all the known sources of damp, give it some time to dry out, and then see what's still getting wet. When we bought our 1890s house we got all the same advice. It is now dry without recourse to expensive and pointless "damp treatments". It's snake oil...

Read the rising damp myth

I'm sure once you fix leaky pipes, guttering , flashing etc your damp problem will go

@CheeseBadger

We have damp at the base of internal walls. Any suggestions?

You just need to find where the water is coming from. Is there any plumbing there? Furniture against the wall? Bathroom nearby? Pile of rubble in the subfloor void? I can guarantee that it isn't rising damp, but beyond that, it is really a case of scratching your head and working out where the water is coming from.

We had a wet internal wall base. Took me 18 months to work out the neighbours weren't clearing their gutters. Rainwater was splashing onto the front path, bouncing against the wall beside the front door, soaking through the external brick and into the plaster for about 4 metres along the hall, just above the skirting board.

That was a right puzzler 'til we worked it out. It would have been diagnosed as rising damp if we'd asked a man with a damp meter...

Also, we do need to lower the floor level outside and sort out the french drains as they are not wide enough

Then you need to do that FIRST before you look for other sources of damp.

It's in more than one place - partly along most of the party wall, partly along the understairs cupboard wall.

In the adjoining house, many years ago the owner decided to deal with very bouncy floorboards in the back room by removing them & filling the void with asphalt

Their internal walls were always damp but ours weren't.

The house changed hands relatively recently & was extensively renovated. I hoped they might dig out the asphalt, but they left it in & had internal damp proofing throughout instead (hacked off plaster etc)

Our damp problem dates from then...

The floor between the party wall & the understairs cupboard wall is also solid.

I honestly don't know how we can deal with it

leaky flashing

what is this please?

We too have Rising Damp, we too had your snake oil man out and I was not convinced he got to the source of the problem, therefore we still have the problem.

We think a gardener in the past put concrete into area between wall and patio and perhaps this changed the old damp course level? This summer dh hired a digger thing and dug down into that concrete but we also noticed what looks like concrete smeared onto the wall is cracked. IS this leaky flashing?

ie we didnt use him.

@SeetheseeyessogreenIcanstarefo

Flashing is the strip (sometimes lead) that seals the start of the roof tiles to the ridge / chimney

Ps - if you have cavity walls, just because the only damp patch is at the bottom of a ground floor wall, doesn't mean the damp is coming through from there. A leak in the roof could filter down and then cause the damp.

It could also be damaged render though which is penetrating damp.

I've currently got a bit of a mystery damp patch in a 1900 house.

Previous owners have spent money on damp proofing that hasn't worked if not made the problem worse.
Houses are meant to breath.

Before getting anything fixed I wanted to have a good idea of what could be at fault.
At the moment it looks like there are cracks in the guttering.

OP do not pay for a DPC. Use your money to address the various issues you have identified, none of which should be that expensive to put right. There is no quick fix to sorting these problems out and letting the place dry out properly. Speak to local builder and prioritise the work. Get the external jobs done now before the winter. The single glazing is the last thing to address I would say unless you have rotten and leaky window frames.

Lapdance It sounds likely that the asphalt is bridging the original DPC. Before your neighbours stuck a second DPC in at a higher level much of the moisture would have been escaping through the plaster and into the air through their side of the party wall. Now it can't get out through their side, so it's crossing the wall and coming out of theirs.

Even if there was no original DPC, there should be enough clear ventilated space beneath suspended timber floors to allow moisture which does come out of the ground to diffuse out of hidden brickwork without causing damp in the joists. Either way, your joist ends are likely to have started rotting if they have become damp.

I've always thought the party wall regulations should apply to this sort of thing. It can cause so much damage.

^ out of your side of the wall, not theirs...

It could also be damaged render though which is penetrating damp

I think you could be write - its damaged render that we have....ie concrete smeared over the bricks and its cracked....

but ours started on the inside wall... now its all along outside wall and a patch on inside wall.

Cheesebadger that's my assumption too. So we're a bit stuffed

There never was a DPC in the first place - houses were built 1880s/90s when there should have been, but up north where they didn't bother.

Walls are solid. And, although mid-terrace, built at different times - ours was added on to theirs.

Short of burning it down & rebuilding from scratch, what can we do? If we had a new DPC put in our side, should it be higher or lower than theirs to chase it back to them & make them dig out the asphalt?

(Houses go door-window-door-window, all with solid floors in hall/under stairs & suspended floors in between - apart from the asphalt....
We had joists/floorboards replaced that side 30 years ago)

I may have been wrong.
[[http://webarchive.nationalarchives.gov.uk/20120919133824/www.communities.gov.uk/documents/planningandbuilding/pdf/133214.pdf] This document] suggests damp proofing does fall within the scope of the party wall act. I'm not sure exactly what you can do about it now the work has taken place though. The laying of the asphalt (depending on when it was done) almost certainly wouldn't have flown with council building regs either. So there are enforcement options. The best way is always going to be to try to get the neighbours onside though. Have a chat with them, explain what's happening, and keep the legal stuff as an act of desperate last resort. It will cause many other problems if you're having a documented dispute...

Great linking skills. <a class="break-all" href="http://webarchive.nationalarchives.gov.uk/20120919133824/www.communities.gov.uk/documents/planningandbuilding/pdf/133214.pdf" rel="nofollow" target="_blank">This document - specifically sections 4 and 5...

Thank you

I'll have a look next time on the computer (phone screen too small)

how could damp be coming from the ground on internal wall?