Damp - To strip off the walls and inject chemicals, or not?

[lostinfens]

Just found this forum, it's v interesting--

I'm surprised to hear people still banging on about "rising damp". It is a myth in the vast majority of houses and one perpetuated by the Damp Proofing industry with the aid of mortgage lenders.
Under no circumstances would I allow a Damp Proofing Company through the door. Most "dampness detectors" merely measure conductivity & would find "damp" on the moon.(The term damp is a misnomer as damp is an adjective).
Putting sand cement render in 19thc houses never cured any dampness!
Rising dampness can only occur where there is residual moisture, even a bridged damp course will not necessarily result in measurable increase, but will aid the possibility.
There are any number of reasons for the presence of moisture in a dwelling, the last remedy is allowing a bunch of idiots with chemicals loose upon your house.

 

[MrHfromBath]

Thanks for your views lostinfens, another interesting opinion.

I have now just got into the house and have had a look at the situation. The walls don't feel damp, but the plaster at the base of the ground floor is in bad condition. After stripping some wallpaper it just crumbled in some places. The walls however don't feel wet.

It is clear that damp has been a concern before as some kind of damp paint has been painted on the walls up to about 3 feet high. I also checked for a DPC and despite the age of the house C1890-1900 there is a slate DPC. There is just one airbrick per room at the front and none at the rear. My next job is to look under the floorboards and see what is going on under there. The airbricks are certainly partially blocked and don't look sufficient to me.

I need to decide what to do soon before progressing, but my current inclination is to get adequate sub floor ventilation added, have the walls replastered, ventilate and heat the place and avoid the whole chemical damp treatment. I am keen to do the right thing and not make a decision I later regret, but I certainly don't want to waster money.

Tomorrow I'll be taping some foil/polythene to the wall as has been suggested by John, etc.

Any other opinions appreciated....... Thanks.

 

[lostinfens]

I'm not surprised that you found a slate dpc. They were all the rage once & I've yet to find 1 which has "failed", despite hearing that from dpc companies.
Even where there is movement of brickwork, which is rarer lower in a wall, & there is a crack in the slate , the chances of dampness is miniscule.
Avoid chemicals-in particular any anti woodworm stuff- that stuff is toxic.
If you are in any doubt try putting a brick in a puddle, then bedding another on top with a slate dpc, hell will freeze over before the slate "fails". Even without the slate rising dampness would be slow & prob evaporate in no time.

 

[mikethehat]

I've sent some time reading about the subject, very little personal experience however.

I agree with Lostinfens. Would expand on his point about cement based products in older buildings something to the effect that:

Traditional lime products are breathable and allow moisture to migrate out of the walls (and usually outside through all the drafts they used to have). Modern cement products and plastic paints aren't breathable and their application to porous materials can trap water or push it into places where it becomes obvious as 'damp'

If your house has a modern cement render on the outside this might be trapping water inside.

Re-plastering the bottom of the walls will be done in modern plaster which may then cause problems of it's own.

If you do plaster work, consider doing it in lime. I am and I'm quite enjoying it.

Good luck!

 

[Bedge]

If anyone wants to chemical DPC my property for free to present a case about its effectiveness you can take as many before and after photos you want! (Plastering must be inc).

 

[joe-90]

You can get DIY damp proofing in a cartridge to fit caulking guns that you inject into the mortar course.

 

[Possel]

If anyone wants to chemical DPC my property for free to present a case about its effectiveness you can take as many before and after photos you want! (Plastering must be inc).

If anyone wants to see an old house that demonstrates how dampness dries out when you sort the issues of water ingress, I have done this in the last 11 months (see http://houseintheenchantedforest.blogspot.com/). There is no DPC or modern materials - just sort the roof, gutters, high ground above the floor level and ventilation.