shed Damp can be a major issue in the home. Find answers to questions or post your own here.

[lloydy b]

Hi there,
ive a timber framed shed with ply sheeting thats rendered with a damp proof membrane on the outside of the building,all this is fixed to the timber studwork which is on the inside.The floor is a concrete slab with liquid dpc solution over it and there's two courses of brickwork around the perimeter of the slab with a dpc on top of them where the soleplate and stud work sits.
My problem is that i have a humidity meter in there and the readings are always so high bordering on the 70% mark most of the time and even though the place has windows and vents i struggle to get the levels down.The size of it is 18"x8"...has anyone any ideas as how to get the levels to a livable environment?thanks

[ALDA]

COLOUR THE EXTERIOR ROOF AND WALLS WITH WHITE OR ALUMINIUM PAINT TO REFLECT SOLAR RADIATION AND SO REDUCE INTERNAL TEMPERATURE WHICH WILL MAKE THE HIGH HUMIDITY MORE TOLERABLE.

ALSO, YOU COULD TRY USING A DE-HUMIDIFIER FITTED WITH A HUMIDISTAT.

[lloydy b]

ive thought about a dehumidifier but there are so many out there and would it have to be running continuously?Also is it a good idea to run a low voltage heating device to soak up any moisture and keep that on too?

[ALDA]

THE HUMIDISTAT WILL SWITCH THE DE-HUMIDIFIER ON AND OFF AT THE REQUIRED MOISTURE LEVELS/SETTINGS SO THE UNIT WILL NOT NECESSARYLY BE ON ALL THE TIME.

ADDITIONAL HEATING WILL PERMIT THE AIR TO HOLD MORE WATER SO MAYBE ONE BENEFIT WILL CANCEL OUT THE OTHER.

YOU WOULD HAVE TO SUCK IT AND SEE SO TO SPEAK.

ALDA.

[lloydy b]

thanks ,it makes sense to try both of them so i'll look into that,all the best Lloyd

[lloydy b]

I'm now a little confused...i stuck a protimeter into the timber studwork to check for damp and it read around 13% so ok there,i did ceiling joists.. also read low on the meter but when i pronged the celotex boarding i have on the floor it read 83% which was the reading with the prongs just into the silver paper.As i stuck the prongs through the middle of a board the reading was around 15% so the meter is telling me the surface paper is damp and the rest of the board isn't!!The slab reads 13% underneath the boarding so any ideas how the surface paper seems to be the only damp thing in the room,is it something to do with it being reflective ,or silver or something?

[ALDA]

MIGHT HAVE BEEN A THIN FILM OF CONDESATION ON SURFACE AT THE TIME YOU DID MEASUREMENT!!!

TRY AGAIN WHEN SHED IS AIRED TO REMOVE ANY RESIDUAL MOISTURE TO EITHER PROVE OR DISPROVE THIS!!!

OR

MAYBE IT IS DOWN TO THE CONDUCTIVITY OF THE SILVERED BOARD (LITTLE RESISTANCE)!!!

WHAT IS NIGGLING AT ME ABOUT YOUR PROBLEM IS;
WHERE IS THE MOISTURE COMING FROM INSIDE THE SHED (IF IT IS WATERPROOFED AND DAMPROOFED) TO GIVE A HIGH HUMIDITY READING?

IT MIGHT BE WORTHWHILE COMPARING READINGS FROM ANOTHER HUMIDITY METER WITH THE ONE YOU HAVE ALREADY TO ELIMINATE THE POSSIBILITY OF AN ORIGINALLY INACCURATE READING BEFORE PROCEEDING WITH THE MOISTURE REMOVAL AND HEATING OF THE SHED.

CHEERS,

ALDA.

[lloydy b]

yep its niggling me also,cant understand whats going on will have a go with another meter
thanks Lloyd

[lloydy b]

Have been told it could be an atmospheric problem so maybe its a problem with the outstide air,i don't know.The roof is tiled and battoned with slating felt underneath with insulation in the ceiling joists just like anywhere else though i have no plasterboarding on them at the moment.Another thing is that the building is at the bottom of my garden which is not the dryest of places and its surrounded by trees.

[ALDA]

AIR IN AMONGST TREES/SHRUBS IS ALWAYS MORE HUMID AND SO AS YOU STATE IN YOUR LAST POST IT COULD WELL BE THE CAUSE OF YOUR PROBLEM.

SO IF YOU DO AS WE HAVE PREVIOUSLY DISCUSSED, I THINK THESE WILL BE THE ONLY REMEDIES AVAILABLE TO YOU APART FROM RE-LOCATING THE SHED TO A MORE OPEN ASPECT!!!

[lloydy b]

thanks for your help i'll get into it at the weekend

all the best

Lloyd

[ALDA]

YOUR WELCOME LLOYD.

IT WOULD BE INTERESTING TO KNOW THE OUTCOME.

REGARDS,

ALDA.