/ DIY "cream" injection damp proof course

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gethin_allen on 14 Oct 2016
I'm having a few issues with damp in the kitchen. So I'm guessing the options are rising/penetrating/condensing damp.
I've tried to isolate the problem and have currently got so far as thinking there is a rising damp issue.
The roof and gutters and new and in good condition, the outside render (stone chip finish) is in good condition but not painted or treated any way.
There are two externally vented extractor fans which are almost always used when cooking.
The wall is a early 1900s two skin brick construction without significant cavity or cavity insulation and it's put together with horrible black fly ash mortar.

I was considering paying to have a pressure injected DPC installed but have come across loads of people using a cream that's injected at low pressure from a caulking gun type applicator into holes drilled in the mortar course. This seems incredibly easy (too easy in my mind) and I could simply and cheaply sort it out myself.

There appear to be reputable companies (eg.Sika) producing this stuff so there must be some basis to it.
Has anyone on here got any experience with this stuff? anyone got any good tips?

Thanks all,

Gethin
Toerag - on 14 Oct 2016
In reply to gethin_allen:

It's cavity wall, yes? Then it's unlikely to be penetrating damp as it's rendered (rain will drive water through the vertical joints in un-rendered brick). Where actually is the damp, at floor level, half way up a wall, in a corner etc? What are the damp symptoms - black mould, blistering paint?

Is there a damp-proof course at all?
Defintiley don't bother with an electro-osmotic DPC, they don't actually work (I know, I have one!)
gethin_allen on 14 Oct 2016
In reply to Toerag:

Hi Toerag,
The damp is visible in various places along the wall and into the corner. It's around 2 foot up the wall where the wall isn't tiled and then in other places where the wall is tiled it's higher at around 4 foot, just above the tiled upstands on the work surfaces.
The paint is a kitchen specific wipe clean product that and it's blistering off the wall. I've no idea if there is a traditional DPC, I haven't found one.

I'm not sure if I'd call it a proper cavity or not, it's two layers but there's only a very slim gap between the layers.
starbug - on 14 Oct 2016
In reply to gethin_allen:

I used an injectable cream on our chimney breast, drilled holes every 10 cm into a mortar course
a brick up from the floor. It worked perfectly.

Stuff I used was:

Kiesol C High Strength DPC Injection Cream 310ml from Permagard.

Their sales people are very helpful.

sales@permagard.co.uk or 01179381596 Monday - Friday, 8am - 5pm.

NB I am not connected with them in any way beyond using the product.
Toerag - on 14 Oct 2016
In reply to gethin_allen:

OK, so it's not condensation damp, but could be penetrating or rising damp. How are ground levels outside? Our house was built around 1895 (granite rubble walls, no DPC) and the ground had built up over the years. digging down and making a french drain has helped.
I can't comment on injectable DPCs other than logically they're only going to reduce the damp, not eradicate it. The cream will seep / creep through voids and mortar shrinkage gaps but I can't see how it will stop damp rising through solid brick and mortar.
gethin_allen on 14 Oct 2016
In reply to Toerag:

Regarding ground levels outside. I live on a hill with a 70 cm drop from my internal floor to outside (over the neighbours side), you'd think that would make things nice and dry inside.

I'm wondering if there could be a build up of moisture under the floor and held back by the retaining wall.
Should there be weep holes in this wall? I wonder what would happen if I drilled a 20 mm hole right through the wall below my floor level?


John2 - on 14 Oct 2016
In reply to gethin_allen:

My house is of 19th century rubble construction, walls 2 feet thick. Well before I moved in, the external walls were injected with a silicone DPC which has been completely effective. However, one of the now internal walls which was external before the house was extended was not treated at the same time and showed significant damp when I bought the house. I've injected it with Dryzone cream, which was a pretty easy job (I hired a professional SDS drill). That was four months ago and moisture levels have definitely dropped since then, though perhaps that's just due to the dry weather we've been having. Everyone says it take between one and two years for a wall of that thickness to dry out.
gethin_allen on 14 Oct 2016
In reply to John2:

That's exactly what I wanted to hear and the very product I was looking to use. I already have a big 5 kg SDS drill so that's the easy bit I just need to get hold of the sealant.

How far did the stuff go (holes filled/tube) I don't really want to buy too many of them at 15 each
JimmAwelon on 14 Oct 2016
In reply to gethin_allen:

It's not in the true spirit of DIY but I have had two timberwise.co.uk surveys in properties I have been interested in. They don't just do timber and my two cases were not related to timber at all. For 150 they did a survey and gave a quote for the work. The first one meant I pulled out of a sale and the 2nd one meant I got the price of a purchase dropped. You can take them up on the work or DIY but in my mind 150 is good for an expert opinion if UKC doesn't solve it for free.

John2 - on 14 Oct 2016
In reply to gethin_allen:

It's designed for brick built walls like yours, not for rubble walls like mine. I suspect that with a brick wall if you inject it into the mortar course then the recommended quantities will be fine (when you inject it into something solid the gun gets pushed back). With a rubble wall (as stated on the Dryzone web site) I had to use quite a lot more.
cha1n on 16 Oct 2016
In reply to gethin_allen:
I've just bought a victorian terrace that's got lots of evidence of damp in the past and have therefore done a lot of investigations into damp in these properties.

Is your kitchen in an extension at the back or is it in the main building? Is your floor concrete or suspended timber? Are the walls rendered in any way internally or externally? If plastered internally, does the plaster go all the way to the floor? Does the damp wall have a window in it? Are you sure the seals around the window are OK? Does the external window sill function correctly (is there a drip installed, etc?). Is the external ground level higher than internally?

Rising damp appears to be a bit of a myth and most issues with damp are because of poor ventilation or inappropriate building materials/techniques.
Post edited at 10:14
thommi - on 16 Oct 2016
In reply to cha1n:

"Rising damp appears to be a bit of a myth and most issues with damp are because of poor ventilation or inappropriate building materials/techniques."....

This is very true. It could be any number of factors, is your cavity air or does it contain insulation. Moisture could well be bridging. Is you plaster board dot and dabbed in to a brick or block wall? Moisture loves dot and dab for migrating through. It is quite a bit more involved than just accepting anecdotal evidence I'm afraid and as the poster said above more often due to construction/retrofit insulation or ventilation issues.

I wrote my dissertation on interstitial condensation so do know a little about this sort of thing. I think you need to spend a bit more time looking at your property.

Tom
cha1n on 16 Oct 2016
In reply to gethin_allen:

I see you've answered a few of my questions already. I suggest you hold off of retro-fitting a dpc for now and do a bit more research. There are situations where they are appropriate but my research indicates that it's not very often.

Unforunately I'm renovating my house and don't have much time to commit to explaining everything but I suggest you do some research on traditional building techniques. These houses were constructed with breathable materials (such as lime mortar) which will absorb moisture but also allow it to evaporate. The building techniques were not perfect, windows weren't perfectly sealed, there were gaps in floorboards, etc, there was ventilation there.

The use of concrete and modern plasters on these buildings are creating water tight seals that aren't allowing moisture to evaporate. Your render is most likely concrete which is initially water proof but is very liable to cracking and once the moisture gets in behind it, it won't let the moisture escape. Similar situation for modern plasters. If they are walls that get very cold, you can get issues where the dew point can occur within the wall itself (the temperature at which vapour will condense).

This is a good website and can get you started but there's lots of good information out there; https://www.homebuilding.co.uk/?s=damp

Good luck.
thommi - on 16 Oct 2016
In reply to cha1n:

Although I should add that 'rising' damp does occur, it just occurs an awful lot less that dpc firms and associated chemical manufacturers would have you believe. You need to think in terms of letting the fabric of the building breath, not sealing away any migrating moisture.
thommi - on 16 Oct 2016
In reply to cha1n:

Bang on.
cha1n on 16 Oct 2016
In reply to thommi:

Good to know the research wasn't for nothing! I've been spending my evenings researching interstitial condensation as I want to insulate my external walls (internally) and it's opened many new questions regarding shifting the location of the dew point, how to control vapour, etc. Hard to explain to my partner why it's taking so long to decide how to insulate the walls, "just get it done". Interesting stuff though.
thommi - on 16 Oct 2016
In reply to cha1n:

"Interesting stuff though"....

To a very small number of quite strange people.

But yes, it is. When you look at some of the 'skill' that goes into constructing new builds in particular, it really makes you appreciate the virtue of homogeneous solid walls, aside from the thermal inertia.

Have you looked into pavedentro and lime plaster?
cha1n on 16 Oct 2016
In reply to thommi:

Yes, one of my favourite things is discovering the complexities involved in things that appear simple at first glance. I've not heard of pavedentro, so I'll look into it. Appreciate the info.
wintertree - on 16 Oct 2016
In reply to cha1n:

> Rising damp appears to be a bit of a myth and most issues with damp are because of poor ventilation or inappropriate building materials/techniques.

Unless you live in a sandstone house in a lime rich area and the acidity of the groundwater - from ground higher than the floor - has disolved the lime out leaving thoroughly porous rock behind...

We ended up waterproofing the inside of all the downstairs walls with swimming pool tanking (Soverign K11) up to 2 meters above floor level.
Post edited at 12:27
gethin_allen on 16 Oct 2016
In reply to cha1n:

I've made a few test holes and found that in one part there is a plastic DPC and above this no damp. In another place there is no DPC and significant damp. In another part the wall was repaired using modern cement and brick and in this area there is no damp issue. I don't think it's condensing moisture as although the wall is fairly cold the moisture is coming out behind a waterproof paint on the upper part.
NottsRich on 17 Oct 2016
In reply to John2:

Thanks for this, exactly what I wanted to hear as well! New house (built 1900), and an internal wall (which used to be external until perhaps 15 years ago) is showing damp upto about 2 foot above external ground level. Not DPC. It's plastered and the paint is peeling, with visible wet patches. Only recently noticed it, probably due to the colder air causing 'venting' moisture to condense on the surface and not evaporate away as quickly. It's not condensing moisture as it's far too localised. At the moment I'm thinking of removing the plaster back to brick in the lower portion of the wall to let it breathe, or to inject goo into it to stop the damp moving up. Very sceptical of these goos but have heard good things so I'm tempted to try it before large scale decorating.
gethin_allen on 17 Oct 2016
In reply to NottsRich:

I've just bought a load "Ultracure" from Platinum Chemicals on E-bay where it's about 7.50 a 310 ml tube rather than the other equivalents which are about 16 a tube over the counter. I would say I'd give you a review when it's done but it takes a while to cure and then for the wall to hopefully dry out.
cha1n on 17 Oct 2016
In reply to gethin_allen:
I think you'll find there's a bit more to it than just adding a dpc. If it's anything like my house, there will likely be a layer of slate above ground level. In my house the suspended timber floor in the extension has been replaced with concrete which bridged the original dpc. There was also a concrete plinth externally which was bridging the dpc on the outside.

Things like water proof paint sound like a bad idea, I try to think of it as a water proof jacket versus a bunch of wicking layers. Yes a wicking layer will get wet but it will also dry out quickly. With a water proof you're stuffed once it gets wet inside. Hope you sort it anyway.
Post edited at 17:11
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gethin_allen on 18 Oct 2016
In reply to cha1n:

> I think you'll find there's a bit more to it than just adding a dpc. If it's anything like my house, there will likely be a layer of slate above ground level. In my house the suspended timber floor in the extension has been replaced with concrete which bridged the original dpc.

this could be the case as it has a relatively new concrete slab floor although the house has suspended floors in the living rooms and solid original tiled floor in the hallway.


> Things like water proof paint sound like a bad idea.

I know what you mean here, the waterproof paint (crown kitchen and bathroom) is only above the work surface and the tiled upstand so I hoped the wall would have a enough uncovered surface below this.

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