Rising Damp

[Riley'sLife]

After the rainy season I'm going to start renovating the in-laws' single storey house. The walls are built of concrete steel reinforced pillars, with either block and mortar, or brick and mortar between these structural pillars. The walls are rendered with a sand and cement mix externally and internally.

The walls have rising damp creating effluorescence and staining on the lower 9 inches of the block/brick wall rising to 24 inches at the concrete pillars where capiliary action has enabled the damp staining to rise higher.

I want to raise the internal floor level by 9 inches throughout and would normally (if I was doing the job in the UK) also lay an impervious menbrane such as plastic Visquene on dry compacted sand before laying the concrete and also fix some barrier such as Newtonite Lath (corrugated bitumastic) to the lower part of the walls to a height of 1metre to ensure that the new internal plaster remains unaffected by the damp walls. Presumably injecting a silicone based chemical into such porous material as block or thai brick wont work especially as they seem to be full of cavities anyway and the drilling would be very "hit and miss" and would perhaps disintegrate the block or brick.

Not surprisingly, I haven't been able to source Newtonite Lath, Visquene or DPC Injection fluid so far in Hat Yai and Songkhla. The best Thai advice I have had from the builders merchants is "put a lot of paint on the wall" !!!

I could vent the existing walls and build a second wall internally, but frankly the building doesn't warrant the cost, as new foundations would have to be excavated to take the weight.

Anyone ever tackled a similar rising damp problem in Thailand successfully?

Anyone know of any surface coating available in Thailand that could be applied to the walls internally before plastering or dry-lining.

Ideas, suggestions or alternatives anyone?

[lopburi3]

Is there perhaps a broken water pipe under the cement floor? If that is the source of the water perhaps redo the plumbing along outside of house.

A good cover is to use half wall high tile covering on wet walls. That will cover the moisture and is cheap and attractive.

I did have to resort to lots of paint one time to cover high on outside wall where they must have used 90% sand. Just kept covering until it stopped soaking in and never had any more penetration.

[sbk]

Our paint flakes off. Rising damp is always a problem, doesn't mean a broken pipe just means the rainy season is upon you and the water table has risen quite high. Wish we'd built our place on stilts now.

[chownah]

I would check the drainage first to see if the problem could be fixed that way. A perimeter trench backfilled with underdrain consisting of perforated pipe or perforated drain tiles placed as low as is practicable and backfilled with drain rock. This assumes that either the water will flow away somewhere or else you might want to try to add in a sump and sump pump (float controlled) to remove the water. Just a thought.

Also be sure that roof runoff for the house AND any other building close to the house are not adding to your problem...also if you want to try the underdrain and need to use a pump then try to not let the roof runoff dump into the drain or else you'll have to pump all the runoff water too. Sometimes you need to bring some more dirt in to make low berms to direct the rain water and roof runoff off in a safe direction.

Edited October 28, 2005 by chownah

[Riley'sLife]

Thanks for all the input guys.This is definately a rising damp problem caused by the usual lack of any damp proof membrane in the wall and floor construction.

There are no water pipes below floor level. I know this because I have just connected the newly arrived Government piped water to the property, and this problem pre-dates the new water pipes. Until last month they used water from the well! The wall tile idea may work but I'm not too convinced about the aesthetics of wall tiles in every room. There is no penetrating damp, only rising damp.

The overhang of the roof is almost 1.5metres and the first thing I did before the rains was to fit rain gutters and rainwater pipes so there is no problem caused by obvious surface water. It is, I am certain, plain old rising damp. The rains here have been pretty relentless in the last few weeks and the damp is still only evident in the same places. I dont think that it will be viable to eliminate the problem (ie to stop the rising damp -as this would require the installation of a damp proof course in the blockwork, chemical injection in the concrete and a new floor with damp proof membrane.) All far too costly.

The best I can hope to do is try and stop the damp from becoming worse and spoiling the proposed new decoration.

I used to have exactly the same problem with some properties in Spain years ago. I solved the appearance problem by replastering after sealing the walls with Newtonite Laths that I transported by car and trailer from the UK. It became a nice little earner as most property there, built in the 80's, had damp problems. Newtonite would be too costly to transport here. It weighs a ton!

The father-in-law says that the damp wasn't there before the massive floods that hit Songkhla in 2000. He built the house. Mother-in-law says it has always been damp!

Really the place needs a bulldozer, but they are happy there. We are building a new place for ourselves on land they have given us so I feel a bit guilty with them living in such a house and want to try and help if I can.

I am really hoping to find a cover-up solution to enable me to decorate over the damp patches.

[chownah]

I'm curious. When we built our house we did not use any waterproof membranes and there is no 'rising damp' problem. We did make sure that we had good perimeter drainage as I mentioned before. I wonder what's the difference if its not the drainage.

[lopburi3]

I was also a little concerned about ceramic tile outside of the bathroom but in the bedroom that we did up to window sill it looks very good and also provides a good lower level defense against the normal wet mop/rag floor cleaning (which is hard on paint or baseboard).

Probably not a problem but another source of moisture here can be a blocked septic tank when the water has to disperse in the immediate ground area rather than into drains.

[sbk]

Thanks for all the input guys.This is definately a rising damp problem caused by the usual lack of any damp proof membrane in the wall and floor construction.

There are no water pipes below floor level. I know this because I have just connected the newly arrived Government piped water to the property, and this problem pre-dates the new water pipes. Until last month they used water from the well! The wall tile idea may work but I'm not too convinced about the aesthetics of wall tiles in every room.  There is no penetrating damp, only rising damp.

The overhang of the roof is almost 1.5metres and the first thing I did before the rains was to fit rain gutters and rainwater pipes so there is no problem caused by obvious surface water. It is, I am certain, plain old rising damp. The rains here have been pretty relentless in the last few weeks and the damp is still only evident in the same places. I dont think that it will be viable to eliminate the problem (ie to stop the rising damp -as this would require the installation of a damp proof course in the blockwork, chemical injection in the concrete and a new floor with damp proof membrane.) All far too costly.

The best I can hope to do is try and stop the damp from becoming worse and spoiling the proposed new decoration.

I used to have exactly the same problem with some properties in Spain years ago. I solved the appearance problem by replastering after sealing the walls with Newtonite Laths that I transported by car and trailer from the UK. It became a nice little earner as most property there, built in the 80's, had damp problems. Newtonite would be too costly to transport here. It weighs a ton!

The father-in-law says that the damp wasn't there before the massive floods that hit Songkhla in 2000. He built the house. Mother-in-law says it has always been damp!

Really the place needs a bulldozer, but they are happy there. We are building a new place for ourselves on land they have given us so I feel a bit guilty with them living in such a house and want to try and help if I can.

I am really hoping to find a cover-up solution to enable me to decorate over the damp patches.

Believe your mother-in-law!

[Riley'sLife]

I guess that the difference may be that the level of the ground outside your home Chownah is much lower than the internal floor level, and the area in which you are situated is less prone to flooding than that of my in-laws. Their house land has a high water table, being on the plain between Hat Yai and Songkhla which presumably encourages capilliary action of the ground water. That's why I want to raise the internal floor level by 9 inches. The best idea would have been to build on stilts. But hindsight is always a winner!

Good point about the wall tiles and the baseboard Lopbury. I know in my apartment in Bangkok the cleaners make a real mess on the walls where they mop the floor. The tiled floor adjoins the decorated wall without a baseboard and the wall there if badly stained. Any chance you could post a pic of the tile work that you did? So far it looks like the best bet.

There is definately no obvious standing surface water on the in-laws land and it is reasonably well drained.

Cheers Rick

[lopburi3]

Have never posted attachment but with luck here is a look - not easy to find open area to photograph in a bedroom used by three girls.

[Riley'sLife]

Thanks very much for the pic. I know just what you mean about girls' bedrooms..messy little things aren't they? I dont think I could even see the walls in my daughter's, what with all the posters, photos,fluffy aminals etc. Your tribe seem very well organised by comparison. It would take all day to find the bed beneath clothes CD's etc., when my daughter lived at home. Strange though how they can change when they have their own home. Tiles look fine, so maybe I'll give it a go in one room and see how I like it. Thanks Lopburi, and everyone for the time taken to reply.

Cheers Rick