Hi all. A bit of background before the query.....
Live in a stone built house we're told dating back to 1790. Its in Pembrokeshire which some of you will know is wetter than many parts of the UK. Have lived in the house since 2017 and am well aware of doing the wrong things to an old house. Have made modest, and sympathetic improvements since moving in. One of the first things we noticed was the high humidity within the property. It was rare to get it below 70% relative. Humidity is actually more of a problem usually in the summer where there might be high humidity outside but then cooler temperature in the house which pushes the internal humidity even higher if we have the windows open. We have focused on increasing ventilation (have humidity controlled extractor on ground floor in kitchen and also positive input ventilation on first floor landing) and managing our own production of moisture to try and manage this rather than doing anything costly and drastic. We're also very diligent in opening windows whenever feasible. All this has had marginal results.
The only cause that we can see for the higher than usual humidity is moisture coming through original flagstone floors. These make up about half of the ground floor area. Whilst I haven't lifted any stones, I'm almost certain there is no DPC underneath i.e. they haven't been lifted. Part of the flagstone floor is covered by carpets and part is exposed. The carpeted areas don't actually seem to get damp but you can see moisture forming on the exposed stones on occasions; Sometimes this is due to condensation but it also happens if something is placed on the stones and covers an area for a short period (i.e. the moisture forming can't evaporate so easily so condenses). The last 8 weeks have been particularly bad as its been so humid outside. We haven't been able to get the humidity below about 80% for any length of time however hard we try and ventilate. As a result, we get mildew forming on furniture which is a right pain. I really want to do something about the flagstones but lifting them is not something I really want to contemplate due to cost and inconvenience. There doesn't appear to be any damp problems in the walls at the sides of the flooring and I'm well aware that that situation may change if you tried to prevent moisture through the stones! So in short, is this a no win situation?!
Live in a stone built house we're told dating back to 1790. Its in Pembrokeshire which some of you will know is wetter than many parts of the UK. Have lived in the house since 2017 and am well aware of doing the wrong things to an old house. Have made modest, and sympathetic improvements since moving in. One of the first things we noticed was the high humidity within the property. It was rare to get it below 70% relative. Humidity is actually more of a problem usually in the summer where there might be high humidity outside but then cooler temperature in the house which pushes the internal humidity even higher if we have the windows open. We have focused on increasing ventilation (have humidity controlled extractor on ground floor in kitchen and also positive input ventilation on first floor landing) and managing our own production of moisture to try and manage this rather than doing anything costly and drastic. We're also very diligent in opening windows whenever feasible. All this has had marginal results.
The only cause that we can see for the higher than usual humidity is moisture coming through original flagstone floors. These make up about half of the ground floor area. Whilst I haven't lifted any stones, I'm almost certain there is no DPC underneath i.e. they haven't been lifted. Part of the flagstone floor is covered by carpets and part is exposed. The carpeted areas don't actually seem to get damp but you can see moisture forming on the exposed stones on occasions; Sometimes this is due to condensation but it also happens if something is placed on the stones and covers an area for a short period (i.e. the moisture forming can't evaporate so easily so condenses). The last 8 weeks have been particularly bad as its been so humid outside. We haven't been able to get the humidity below about 80% for any length of time however hard we try and ventilate. As a result, we get mildew forming on furniture which is a right pain. I really want to do something about the flagstones but lifting them is not something I really want to contemplate due to cost and inconvenience. There doesn't appear to be any damp problems in the walls at the sides of the flooring and I'm well aware that that situation may change if you tried to prevent moisture through the stones! So in short, is this a no win situation?!