do we dig up floor and lay concrete??

[janet]

We have a late Victorian house which has two rooms with very, uneven floors - really noticeable when you walk on them. In the lounge we have some damp in the walls - from the floor upwards. Underneath the carpet is underlay, under this a series of plastic fertilizer bags (ex farm house) and under this a tiled floor - not particularly nice tiles - and these are laid on (possibly) compacted ash or similar. The tiles in the hall were badly broken and had some sort of white deposit on them. Everything under the lounge carpet was understandably sweaty, In our ignorence - pre-period property forum days- we have had the hall floor dug up, a plastic sheet (damp proof membrane) put down, polystyrene sheets laid on top and then concrete.
Following various threads in this wonderful forum I am beginning to have real worries that this was a mistake. We are currently waiting for another set of builders to come and do similar to the lounge and dining room floors. Will this be a mistake? Should we somehow go for a more breathable option? If so - what? Are we going to force damp up the walls? I would like to keep the carpet in the lounge.
We have had areas of the lime mortar raked out and replaced with mortar containing lime to try to cure the dampness - not convinced it's been successful - gutters etc are fine.
Thanks in anticipation.
Janet

 

[middi]

Apart from some enviromental issues there is nothing wrong in using cement floors, D P membrane and insulation.

In your case if you want to use this system, you have to make sure that the DPM is well lapped into the walls DPC and this is in good condition, you do not have to worry about damp coming through the floor or wicking up the walls, in other words if you want to stop damp coming from the ground up you also have to make sure you are taking total control with membranes and DPC,s correctly fitted.

If you use cement and membranes and there is no DPC in the walls, the chances are that you could make the matter worse ( no more so than tiles and fertilizer plastic bags though).

It is important to remember that if a solid impermeable floor exists without any DPM, no other impermeable floor coverings should be used above this, as the previous occupiers did, otherwise heavy condensation will form between the two layers which can only escape through the base wall and back into the room.

Where damp and humid conditions prevail, it is a question of balance:-

1).......You take total control, (with modern materials if you want to )

2)..... .You use traditional breatheable materials and leave it to the elements to keep things dry.

The problems usually start when we " half" interfere with one or the other, use incorrect materials or incorrect fitting, and waste time and money.

 

[biffvernon]

Apart from some enviromental issues there is nothing wrong in using cement floors.

Ah, those environmental issues. Using cement does wonders for the size of your carbon footprint.

 

[middi]

what can we do Biff, nuclear bombs, mother in laws, cars and cement are an unnecessary evil, it is up to the individuals conscience as to how much attention they give them.

( mind you mother in law in cement is not such a bad idea !!!)

 

[MdB]

If you use cement and membranes and there is no DPC in the walls, the chances are that you could make the matter worse

The 1970s part of my house has at least two layers of concrete on the floor and it is bone dry so probably has some sort of membrane under it. The walls are concrete block with cement render and I've not yet found any sign of a DPC. The top layer of the concrete floor was laid after the the walls were rendered so the water wicks nicely up the render. This has given us damp patches all the way around the bottom of the walls and the render has failed. When I dig through the top skim of plaster I just get damp sand falling out...

My point is, get the DPC / membrane issue wrong and you will cause yourself problems.

My solution is to lower the ground level around the house + add some french drains so as to lower the water level which will be a fun job this summer. If this doesn't work, we will have to think about removing the concrete floor and do a bit of investigation.