alternative to dpm and dpc

[guy84]

I though this may be an interesting topic for people to think about and i have not seen much on the web about it.

Here go's:

Instead of having a chemically injected DPC and installing a DPM to the ground floor of my old house (built 1910ish) I decided to strip off all the lime render (that was literally falling off some walls due to years of condensation and a slight bit of rising damp from the previous owner) and then render the bottom meter of the wall using a sand cement render.

I then painted the render to the bottom 1m of the walls and the existing floor slab with several coats of bitumen emulsion ensuring good coverage at the wall floor joint.

I then laid a 50mm concrete floor screed over the bitumen and then dotted and dabbed the walls and then skimmed them. It looks so much better now.

Within a week the room felt dryer and warmer.

Has anyone else used this system it was so cheap to do. it literally cost me about £100 in materials (including tools) and 5 days of work for a room about 3.5 x 4 m.

I honestly think that installing a DPC to an old property can be a waste of money when systems like this are so much cheaper to install.

Some will say its a no brainer installing a chemical dpc if your re plastering anyway, but this method i used saved so much money and it was all work i could do myself.

Anyone else tried this out, i would be interested to hear from anyone who did this a few years ago to see how their room is holding out?

I plan on using this method for the dining room and kitchen which are on my list of refurb works for the rest of the year.

 

[gregers]

fair play to you,BUT and a BIG but if you defo was certain it was rising damp your house was suffering from then it still is.

 

[freddiemercurystwin]

Traditionally utilising bituminous coatings on the inside of structure have always required a layer of blockwork or similar to hold them against the wall so it'd be interesting to see how it fairs long term.

 

[gregers]

think op,s on about good old fashioned black jack.

we used to use it many moons ago for a council who preferred black jack then a chemical dpc,but we used to paint it on the walls (3 coats)then blind it with sand then render it and set.

 

[freddiemercurystwin]

So you're relying on blind faith that the damp in the wall will not blow it off the wall then? Guess its fine if there's only a bit of damp in the walls?

 

[mac391]

The lime render that was on your walls allowed the slow release of moisture, hence you had very little damp in your 100yr old house. Now that you have coated the subfloor with bitumen, any moisture under it(and there will be as there is no dpm) will have nowhere to go and will be pushed outwards into the walls ensuring your slight rising damp problem will soon get much worse and can be pushed higher than the 1m coverage of bitumen you have.
It will come through in patches where every dot (dot n dab) is.. i've seen this happen at ceiling height on old properties.

If you had no real damp issues it would have been best to repeat what the original builders did and use a lime mortar, it probably would have lasted another hundred years.

I've never tried it, but how well does dot n dab stick to bitumen ???

I wouldn't start the other rooms just yet if i were you !!