Damp pammet floor 18c cottage

[k99mn]

Hi after some advice, we have an 18c timber frame cottage that we’ve spent years and money restoring and all has gone well …so far. the House is built direct to ground and ground internal floors are pammet tiles laid on dry sand and pointed with mortar ( another job to do) our floor covering is loose laid laid mats. The previous owners had fitted carpets, these were removed during our ongoing reno action. During our renovation the carpets were removed which revealed a soaking wet floor, we removed some of the floor which revealed a large plastic sheet under the sand that the pammet are sat on, this sheeet was removed as far as possible and to date all has been well. However since we’ve had the humongous amount of Rain recently a large section of the floor is very very damp so much so that my moisture readout is ‘OL’. To this point ive not been particularly bothered believing that nature will take its course and eventually it will dry out…….this is taking slightly longer than I had expected, There are definitely no pipes under the floor so the wet is from the ground , should I be concerned? If so what are my options? Remove the floor and replace the plastic mat? Dehumidifier? Or just let nature take its course
any input from those that know better would be appreciated
cheers for now

 

[tobydog]

Hi,

I'm currently taking the same approach and letting nature take its course, however, it was letting nature take its course that caused the problem in the first place. If I had a pammet floor on sand over earth then I would probably let it breath and dry out as best you can. I've been using a dehumidifier for our problem but, as you know, that's only any good for one day at a time.

Quite a few years ago ( 8 - 10?) I took the cement render off the sole plate plinth wall in our dining room. The sole plate only sits above 3 - 4 inches above the kitchen floor which has a concrete base. The bricks, and underside of the sole plate, were in pretty poor condition so, after removing all the rotten wood, allowing it to dry out for a few months, and rebuilding the plinth, I rendered it using lime putty and lime washed it. Up until this year I had pretty much forgotten about it, however, earlier this year I started to see several tide marks appearing in the lime wash and the render felt damp to the touch. Since the heavy rain we're had more recently it has got noticeably worse. To go all these years with no problems to suddenly get obvious heavy damp, it has to be the weather and a rising water table. My concern is that with such a shallow plinth height I don't have enough surface area for it to evaporate quick enough and will cause further damage to the sole plate. I didn't fit a damp proof course due to the very undulating and awkward nature of the plate. It was also very dry when I rendered. I may need to take if off and start again

 

[jdsnape]

Very much not an expert, but we have had similar this year (also in suffolk). Despite the outside ground levels being low, and the floor being breathable we've got a couple of places where the floor is damp, and some of the bricks have some salt marks on them. The water table is just so high at the moment, we are on clay and every time it rains the garden has standing water in it for the rest of the day so I'm not really surprised. We only moved in this summer so I'm planning on leaving nature to take its course and seeing if it is just because of the unusually wet weather we've had.

We did put the under-floor heating on for the day yesterday to try and dry it a little, but it uses a lot of oil! We normally have the rayburn on for cooking anyway so the main rooms are fairly warm.

 

[k99mn]

Thankyou very much for your replies, interesting that both replies are from Suffolk! my damp issue is also only in one particular place and we too are on clay, also interesting is that many years ago (long before modern day I’m guessing) the corner post of the cottage collapsed and consequently we have a wonky house, the corner post in question is also in the area of the damp floor. looks like the nature course is the way forward but will try a dehumidifier in the mean time.
Glad I picked up these posts this morning, because after watching grand designs last night where a couple renovated an old Cornish mill they dug the floor out and before backfilling with concrete they put the aforementioned plastic sheet in to kind of tank the floor, so I was actually considering digging my floor out again and replacing the plastic despite my very minor knowledge telling me thats the wrong thing to do as it’s just going to push the damp to the extremities and eventually rot my lovely new oak sole plate and corner post.
so nature it is unless anybody else would like to join the conversation and she’d some light on our damp issue,
kelvin

 

[jdsnape]

One other thing I should have asked was have you taken a look at the outside wall at the location of your damp patch to see if there is something splashing/dripping against the wall there? We found that our damp patch internally was caused by water running down a drainpipe and splashing off the ground close to the wall. With the volume of rain we've had that had just built up and soaked through the brickwork.