Flagstone floor and damp

Hi, we've just bought a tiny old cottage that is quite damp on the ground floor (the house is below ground level at the back. The kitchen has a flags one floor that is damp along the back edge. The surveyor recommended pulling up whole ground floor to lay a damp proof course. Is there any way around this because we don't want to lose the original floor. The house is habitable...
Thanks!
Sara

You don't need to lose the original floor. If you're careful with the flags, you can relay them on top of the concrete.

RedHerring2 said:

You don't need to lose the original floor. If you're careful with the flags, you can relay them on top of the concrete.

Click to expand...

Thanks for this.. The surveyor suggested taking off a metre high surface from the rooms on the ground floor when doing the work. Do you think this is necessary?
Thanks!

sara101 said:

the house is below ground level at the back.

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This is the deciding factor.
Apart from that assume 150mm for hardcore, 50mm sand blinding, 100mm insulation, 100mm concrete (dpm under insulation)
Total 400mm.

But you really need internal floor level 150mm above external ground level, although you probably do not have a dpc (damp proof course) in your walls, so that's nearly irrelevant.

Alternatively, you could lower the external ground level.

RedHerring2 said:

sara101 said:

the house is below ground level at the back.

Click to expand...

This is the deciding factor.
Apart from that assume 150mm for hardcore, 50mm sand blinding, 100mm insulation, 100mm concrete (dpm under insulation)
Total 400mm.

But you really need internal floor level 150mm above external ground level, although you probably do not have a dpc (damp proof course) in your walls, so that's nearly irrelevant.

Alternatively, you could lower the external ground level.

Click to expand...

Oh boy, the house upis built into a bank on a slope, so one bedroom on first floor is at ground floor outside. Are you suggesting they will have to dig deeper to put in a damp proof course?

How old is your cottage? What do you think the previous owners did to combat the damp? My guess is it wasnt always there.
Any damp proofing expert will tell you you have to damp proof everything, the reality is you need to get to the source of the damp and not try and remedy the effects.

Your floor is designed to 'breath' meaning any moisture under the floor will pass through it unnoticed. If you put a DPM in your floor you will push the moisture into your walls thus causing more problems. You will also have to meet building regs and fit insulating etc etc , a lot of cost to hide a problem that will only manifest itself back in your walls.

Have you had any re-plastering done lately? Is the plaster on the back wall lime or cement? The higher ground level wont be helping but assuming this ground level has always been there I would be looking for a source of excess moisture levels. Check all your guttering and drainage for instance, you would be surprised how much damp a blocked drain or gutter can cause.

Your breathable floor was working at some point , what has changed? New plaster , windows , doors etc etc.

Is your cottage listed and if so have you contacted your local conservation officer and discussed things with them?

I would recommend having a read through this site before considering a DPM under your floor.This ki8nd of situation has been covered a lot but it wouldnt do any harm to ask on the forum either.

http://www.periodproperty.co.uk/forum/index.php


Edit to add, you say you have just bought the property, was it lying empty before? I bought an old cottage last year and have been working on restoring it since, when we first opened the door it was very damp. It had stood empty for 3 years. A lot of the damp was caused by poor ventilation and no heating but most was caused by concrete flooring and DPM's that were added in the 70's. We have to pull all the3se up and replace with a breathable limecrete floor.
Our surveyor was a specialist in this type of building and he said the cottage had damp issues and ''saturated brick plinths under the timber frame''.
A month or two of open windows , heating and general living in the cottage cured all the damp issues.
Well , apart from the damage caused by the DPM under the floors, this will take some serious structural work to remedy.

Thanks very much for the link and advice. The house is about 250 years old and the damp has obviously been lived with by the last owner who was here for ten years. I will have a good read through the forum you suggested