hi there i'm running a dehumidifier down my shed and am trying to get the humidity levels down to below 60%.Ive put a liquid d.p.c over the concrete floor and after a month or so of being down i'm struggling to see the levels drop.Today is very windy so i have all the windows and door open and now i have a 55% reading but when i shut it all up tonight i know it will read higher in the morning.The liquid d.p.c was from wickes and once laid do you think it would be 100% in keeping moisture from coming through?
damp
- Thread starter spoonse
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ok its constructed from timber studwork,ply on the outside of that with a membrane for water then eml and two coats of render.On the slab there is a course of two bricks all around the perimeter with soul plate on the top,dpc and then the stud walls,ive laid the solution on the floor around three or four weeks ago and its slightly soft to touch even though its dry but it should be doing the job right?
is this the same case for normal houses as the heating and windows etc can't be on all the time?i have a mould spore of some kind in the shed due to the damp air and i need to keep the rh levels down before i start to bleach and cleanse it all.
Principles are the same, but a house has different thermal properties due to its mass, so internal RH will not change as rapidly as a shed.
Its not the damp air which you need to reduce as this is not in itself causing your mould problem - you will be fighting a losing battle if you try to dehumidify as the solution.
It appears that moisture is condensing and allowing mould to grow, so the most practical solution is to treat the mould with a fungicde (not bleach) and then ventilate (to move the air around and allow evapouration) and insulate the cold surface where the mould is (to prevent condensation forming there)
Its not the damp air which you need to reduce as this is not in itself causing your mould problem - you will be fighting a losing battle if you try to dehumidify as the solution.
It appears that moisture is condensing and allowing mould to grow, so the most practical solution is to treat the mould with a fungicde (not bleach) and then ventilate (to move the air around and allow evapouration) and insulate the cold surface where the mould is (to prevent condensation forming there)
apparently mould reproduces above 65% rh so thats what i'm aiming for at the moment to reduce that reading ,but if i kill it with the wash then hopefully that should be the last of it.So its best to use a fungicidal killer?Does it have a more effective agent in it?thanks
woody is right, the internal relative humidity levels may be meaningless and representative of the external RH levels. Why are you aiming for below 60%? 70 % and above is considered high but readings are only useful when taken in conjunction with dew point temperatures. Are internal surface temperatures below dew point temperature? If so you'll have problems with condensation. It may be that mould is forming on the timber for no other reason than the timber is permanently damp from the elements. Check the timber moisture content with a Protimeter, if it's above 20% then it may well support fungal growth irrespective of condensation levels.
sounds a good idea to check the timber studwork for moisture ,the reason for the 60-70% is when mould spores reproduce and get airbourne.
The outside as i say has a damp membrane sheeting all around it so any outside moisture should be kept at bay,the studs and ply on the inside feel bone dry to the touch but for a true reading i'll need to get a meter,i was hopeing that now ive put the black gunk on the floor this should stop any moisture from pushing up through the slab
The outside as i say has a damp membrane sheeting all around it so any outside moisture should be kept at bay,the studs and ply on the inside feel bone dry to the touch but for a true reading i'll need to get a meter,i was hopeing that now ive put the black gunk on the floor this should stop any moisture from pushing up through the slab
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