Liquid DPC Damp Proof Course Injection Cream

[revelation]

Hi all

 

I was wondering if anyone has and experience of using products like the one below

https://www.restorationuk.com/damp-proofing-products/damp-treatments/product/focus-damp-proof-1l-cartridge-tubes

 

Because its an old house with some instances of rising damp my builders advised that I get a DPC injected, so I went ahead and got someone out to do it, so they have drilled a load of holes in the mortar and injected the mentioned liquid/cream.   They weren't able to indicate how soon it was going to act which wasn't reassuring, my builders and the DPC person argued whether it should be below final finished floor level or above.   

 

The other concern is that in the description of this product it states   "When re-plastering following a Focus damp proof course DPC installation under NO circumstance use a Gypsum based product. Please ask for a Renderpel replastering specification if required"

We plan to dot & dab the walls and liquid screed the floors, which are all generally gypsum based from my understanding.

 

Could anyone offer in insight as to whether I should be concerned or whether it all sounds ok and I'm worrying about nothing. 

[Mr Punter]

It is worth finding out if it is really rising damp first.  Often internal plaster can get damp at low level due to warmer internal air coming into contact with cold external walls, especially at low level, under windows and in corners.

 

What are the walls built from?

[SoldierDog]

You will find quite a lot of information here:

 

http://heritage-house.org/damp-and-condensation/managing-damp-in-old-buildings.html

[TonyT]

Don’t do it!!!

 

investigate further as this solution will not work

good link by Soldierdog

[revelation]

Thank you for the information. The house I am renovating has gone back to brick everything stripped out, old plaster, skirting literally everything.  There were a few areas where the bricks were damp higher up. 
 

My builders who are experienced said that it looked liked rising damp. 
 

Our floors were damp too so they suspected no DPM under the concrete, so we had that dig up and there was no DPM. So we have laid new DPM and concrete slab. 
 

Due to their advice we had already had a so called ‘damp proof specialist’ to inject some of the house already. 
 

 

[revelation]

I forgot to mention that I will be having an MVHR system fitted and the house is a 1930's house.  

We have also added external wall insulation to the outside of the house.

 

However, all the damp/wet issues were apparent before any of the additional works.  They had also remained wet even after the plaster was taken off and the house was getting plenty of ventilation through about 6-7 months while we had no doors and windows in places.

[TonyT]

What did the do to the new dpm when they laid the slab

 

in my opinion 99.7% builders have no idea about damp issues and refer to the damp industry experts who know very little about damp and will just want to drill holes, inject cream, replace plaster with cement based products etc etc 

[revelation]

I am not sure I understand the question, they laid the DPM over the surface they had prepared (stone, sand etc) and then we had the concrete pumped in for the slab.

[Roger440]

On 29/12/2020 at 02:35, revelation said:

Thank you for the information. The house I am renovating has gone back to brick everything stripped out, old plaster, skirting literally everything.  There were a few areas where the bricks were damp higher up. 
 

My builders who are experienced said that it looked liked rising damp. 
 

Our floors were damp too so they suspected no DPM under the concrete, so we had that dig up and there was no DPM. So we have laid new DPM and concrete slab. 
 

Due to their advice we had already had a so called ‘damp proof specialist’ to inject some of the house already. 
 

 

 

Oh dear. Did you aquant yourself with the link above? I suggest you do so asap before you do anything else.

 

Installing your dpc and slab "may" be making it woirse not better.

 

Periodproperty forum is a good source of info too.

 

Im about to do mine. There wont be any DPC or concrete!

[TonyT]

The damp will push under the new dpm and up the wall if the DPM isn’t tied into a dpc.

effectively relocating the damp issue somewhere else

[revelation]

5 hours ago, Roger440 said:

 

Oh dear. Did you aquant yourself with the link above? I suggest you do so asap before you do anything else.

 

Installing your dpc and slab "may" be making it woirse not better.

 

Periodproperty forum is a good source of info too.

 

Im about to do mine. There wont be any DPC or concrete!

 

The DPM and slab were around 12 months ago.  Therefore there isn't any way round that (beyond digging it up)

 

I have owned the house for around 3 years, when it had no DPM there was damp coming through as the concrete floors were damp.

 

What would have been the best course of action? And is there anything that can be done now?

 

 

[revelation]

5 hours ago, TonyT said:

The damp will push under the new dpm and up the wall if the DPM isn’t tied into a dpc.

effectively relocating the damp issue somewhere else

 

I was advised after the dam to get the the walls filled with liquid DPC stuff that I have ended up using.  Is this a really set up?

Would the MVHR system help control the moisture level in the house?

 

Many thanks

[Onoff]

I have an 1865 terraced cottage. Suspended wooden floors, lime/horse hair plastered walls, solid brick walls with no cavity. When I bought it in the early 90s the first thing I did was fit uPVC windows WITHOUT trickle vents & add central heating. The plastering is very thick so to build it up I shot down to Wickes and bought browning or bonding, can't remember which! 

 

I cleared the air bricks front and rear. The house is only 12' wide. Looking at the front of the house, on the RHS, where there's front to back air flow, there's no damp issues.

 

On the LHS however there's an internal corner that I guess is dead air and gets no cross ventilation. Similarly an area by the front door and a patch low down on the party wall midway between front door and problem internal corner. Where I replastered in modern materials the whole area of the "dead air" corner, about 1m in dia is hollow and damp to this day. In that area I spent a fortune and tried the Wickes, liquid injectable damp proof system, popular in the day. It didn't work!

 

The one area that seems intact is the midway point on the party wall where I painted the bricks with the expensive, WATERPROOF PVA (the black can not red back then) and then sand cement rendered adding a 5:1 same "black" PVA mix instead of plain water. I do wonder tba whether my neighbour at that point has damp his side? 

 

Looking back the problem is simple. Lack of ventilation & wrong repair materials used. 

[TonyT]

you need to check the outside ground levels to make sure they are lower than the inside

make sure gutters downpipes etc arent blocked and fully working

no plumbing leaks.

with heating and proper venting they area will dry up.

External walls- Cement render? Cement based mortar?

this all takes time to dry

 

 

 

 

[revelation]

3 hours ago, TonyT said:

you need to check the outside ground levels to make sure they are lower than the inside

make sure gutters downpipes etc arent blocked and fully working

no plumbing leaks.

with heating and proper venting they area will dry up.

External walls- Cement render? Cement based mortar?

this all takes time to dry

 

 

 

 

 

With the external walls, the new part are proper cavity walls which will be rendered, the old part is a double solid brick wall with no cavity.  It had render which was hacked off a couple of months ago and will be externally insulated and then rendered.

 

Our outside ground levels will be a little lower than the inside.  The only area where they are level will have a 5m run of Aco-drains.

 

There is no leakage or blockage anywhere.

[Roger440]

1 hour ago, revelation said:

 

With the external walls, the new part are proper cavity walls which will be rendered, the old part is a double solid brick wall with no cavity.  It had render which was hacked off a couple of months ago and will be externally insulated and then rendered.

 

Our outside ground levels will be a little lower than the inside.  The only area where they are level will have a 5m run of Aco-drains.

 

There is no leakage or blockage anywhere.

 

The damp is coming from somewhere. And is has to go somewhere. So you now have concrete floor with a dpm, pushing it out to the walls. And you are going to insulate and render it outside. So you would, effectively waterprofed / sealed it. So the damp has nowhere else to go other than come out inside. Id guess the render you hacked off was also cement based?

 

Your wall is no different, it has moisture in, it needs to evaporate. It cant, or couldnt, other than internally. If you cover that up with say, tanking, you wont "see" the damp, but your walls will be wet forever.

 

As one of the videos on heritage house say, if you wash you clothes, put then in a bin bag and hang them on the washing line, what do you think will happen?

 

If you left the render and insulation off, i suspect it would dry out in due course. Rule of thumb is 1 inch per month. Its 9 inches thick.

 

It needs to breathe. Lime, lime lime. As per the heritage house site.

 

In a new house, there would be a dpc in the brickwork to prevent this. You could try retrospectively installing, but thats a big undetaking. And runs the risk of the bricks below the DPC being permaently wet, which may, or may not be a long term issue. Theres a reason they use concrete block now.

 

The front of my house is the same construction. It was damp all the time in there. 90+ humidity, permanently. Reduced the ground levels outside, removed the plastic dpc from under the floor, removed the render on the INSIDE. Put a vented cap on what was an open chimney. 12 months later, i can drill into a brick and it comes out as dust, not a slurry. Room sits at 60-65% humidity all the time. Ive still to remove the modern paint off the lime render outside, but it doest reach the floor so im getting away without it.

 

Everything you could want to know is on the heritage house website.

 

These links might be useful too:http://www.mikewye.co.uk/ & https://www.lime.org.uk/

 

 

Edited January 4, 2021 by Roger440

[Adsibob]

On 04/01/2021 at 14:22, Roger440 said:

 

The damp is coming from somewhere. And is has to go somewhere. So you now have concrete floor with a dpm, pushing it out to the walls. And you are going to insulate and render it outside. So you would, effectively waterprofed / sealed it. So the damp has nowhere else to go other than come out inside. Id guess the render you hacked off was also cement based?

 

Your wall is no different, it has moisture in, it needs to evaporate. It cant, or couldnt, other than internally. If you cover that up with say, tanking, you wont "see" the damp, but your walls will be wet forever.

 

As one of the videos on heritage house say, if you wash you clothes, put then in a bin bag and hang them on the washing line, what do you think will happen?

 

If you left the render and insulation off, i suspect it would dry out in due course. Rule of thumb is 1 inch per month. Its 9 inches thick.

 

It needs to breathe. Lime, lime lime. As per the heritage house site.

 

In a new house, there would be a dpc in the brickwork to prevent this. You could try retrospectively installing, but thats a big undetaking. And runs the risk of the bricks below the DPC being permaently wet, which may, or may not be a long term issue. Theres a reason they use concrete block now.

 

The front of my house is the same construction. It was damp all the time in there. 90+ humidity, permanently. Reduced the ground levels outside, removed the plastic dpc from under the floor, removed the render on the INSIDE. Put a vented cap on what was an open chimney. 12 months later, i can drill into a brick and it comes out as dust, not a slurry. Room sits at 60-65% humidity all the time. Ive still to remove the modern paint off the lime render outside, but it doest reach the floor so im getting away without it.

 

Everything you could want to know is on the heritage house website.

 

These links might be useful too:http://www.mikewye.co.uk/ & https://www.lime.org.uk/

 

 

Not had the chance to look at the first link, but https://www.lime.org.uk/products/sublimer-insulated-limecrete-floor.html looks like it might be much better than the concrete slab I had envisioned. Thanks @Roger440!
I'll keep researching and update you all once a RICS surveyor (hopefully one trained by Pete at Heritage House) has had a look.