9129 Damp walls

I wonder if anyone can suggest a solution to this problem:

We're turning half the cantina (one foot below street level) into a living room. We've put down a thick plastic layer and 3 inches of cement and LECA (for insulation) to keep damp from coming up through the floor. But there are also a couple of places where it comes a few inches up the walls. Our original plan was to use wooden battens and leave a slight gap at the top and bottom of the plasterboard. The drawbacks of this are firstly that the gaps will look pretty strange and secondly that the moist air that convects into the room will just sit there at floor level. I imagine a dehumidifier would be needed to get rid of the moisture.

Another scheme would be to seal the plasterboard but to put a grille at the top of the plasterboard at one end the room and an airpump, like in a bathroom, on the far side and at the bottom of the dividing wall to periodically pull dry air behind the plasterboard, past the damp spots and out of the room. The drawback to this solution is that my wife considers it excessively "characterful".

Any suggestions gratefully received.

Category
Building/Renovation

Submitted by Anonymous (not verified) on Mon, 03/24/2008 - 14:19

This was discussed some time ago Stokies, so may be worth looking at the following thread.
[url]http://www.italymag.co.uk/forums/property-sales-rental-advice/8739-problem-water-rising-up-through-floor-house-bought-outside-parma.html?highlight=damp+walls[/url]

Submitted by Anonymous (not verified) on Tue, 03/25/2008 - 06:52

Thanks Geotherm, but that's a different problem. I don't have flooding, just the usual bit of damp in pre damp course walls. I know providing ventilation is all that's needed, just not sure of the best way to go about it.

Submitted by Anonymous (not verified) on Tue, 03/25/2008 - 07:39

try this link then, it may be better
[url]www.italymag.co.uk/forums/building-renovation/5709-dampness-walls.html[/url]

Submitted by Anonymous (not verified) on Tue, 04/15/2008 - 07:10

Hi Stokies, don't know where you are but if you are near me, I can recommned a damp-proofer. PM me for the details

Submitted by Anonymous (not verified) on Tue, 04/15/2008 - 12:19

[url=http://www.oldhouse.info/ohdamp.htm]Old Houses Deal with Damp by Breathing[/url]

This may be helpful as it deals with damp in old houses.Personally speaking we had to remove all the boards from the old walls of our uk cottage and repair what was underneath before our damp

We are restoring an old house contructed mainly from local rubble and cut limestone with some brickwork around doors and windows.The house has had all traces of cement and 'modern' plasters removed (almost) and we are slowly patching up the walls/floors using our own mixed lime mortar.
There is a big advantage to having everything bare if you see what I mean!Any damp areas can be seen very easily and remidied.In one case a lot of soil has built up against a wall so that the level is above the level of the floor inside.The wet soil is causing water to enter the wall and preventing any proper drying of mortar.
Our solution will probably be to dig out a drain and remove the soil to allow this wall to dry.No doubt once we've 'cured' this problem another patch will appear!

While I do realise that our slow approach is not for everyone at least we will know what sort of state our walls /floors really are under the plaster once we finally get to apply it:how many old stone houses are simply rendered over on a metal mesh leaving weak and crumbling areas 'unseen'.
Is this being unfair on Italian builders?Or does it happen?

Submitted by Anonymous (not verified) on Wed, 04/16/2008 - 02:43

regarding the cement steel cage solution to house restoration this is not a fair description of what happens... in the sense that in general that solution is used because the house is basically unstable... i know we have talked about this before and it is very often due to people purchasing or taking on ruins where the internal fillings between the inner and outer wall has washed out over the years...

another reason that you will find this approach used is that a geologist has taken samples of the ground and the house is not stable in that sense too...especially if a new roof is being placed on top and additional weight added.... so i don't think its a truism to blame all Italian builders and indeed geometra/architects for this type of project...

if you have limitless funds the solution is to knock down and rebuild from scratch laying in new modern foundations to carry the old looking house... but its expensive...

as regards the stokie problem... never lay plastic and cement like that...it causes damp to be pulled up...you should have dug out further and piped air in under the top layer of the floor... in fact damp earth with a system to allow air to flow from breathers above ground would most probably have been the ideal solution...

that however is no good to you now... i would not suggest digging up the work carried out already... letting air into the room through vents from above ground will help as you have worked out for yourself... plaster board if that is used as your only way around the problem would be better fixed with the special metal rails... one thing about wood is it will take up moisture and lead it out to the plaster board ...and also it will go rotten... the other thing with the metal is that it has lots of holes ... therefore air is not sectioned off...
if you have enough head height i would also suggest that you aim to get an air gap above the work you have already done,... and then lay in the final paving... or even go for a wood floor on battens...its not very usual here but it would allow you that flow... and then run the plaster board up...

plaster board can be made to look less obtrusive in an old setting by plastering it in a rough way... ie sponging the plaster off in circular motions to give it that grainy look and rounding edges ... its even sometimes best to actually make a feature of it rather than trying to disguise it... ie bring it out further into the room and lay old bricks or tiles on top... either for bookshelves or seating... even lay in a length of old timber to make it appear like one of those feeding troughs that many old house had for animals...

you will know best how it will all look... i wouldn't despair its a common enough problem here ... think big... and get the air holes covered ... i would say there would be little need for a pump if you can get a big enough set of breathing holes...

Submitted by Anonymous (not verified) on Mon, 04/21/2008 - 13:42

Many thanks for the helpful replies.

Shame I heard about ventilated floors too late. All my life I had no idea they existed - now as soon as I put down an unventilated one they appear from a couple of sources and I can even watch one being put down for a neighbour.

You were right about not needing something to pull the air through behind the plasterboard Adriatica - as soon as there's anything of a breeze it's like a wind tunnel. I took a board down today to see how things are going and was pleased to find that, after two very wet weeks, the wall is drier than before the boards went up.

Submitted by Anonymous (not verified) on Thu, 04/24/2008 - 08:09

[URL]http://www.greensteps.co.uk/tmp/assets/1163178050906.pdf[/URL]

if you can wade thro it there's some useful plans for treating with damp walls using internal lining in this doc!