Damp workshop

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    Chris Bunney

    Hi all,

    My workshop (in the UK) is a single concrete block garage (not joined to the house).
    The problem I have is that it seems to always be a bit cold and humid in there.

    A lot of my work tends to shrink badly and warp when I bring it in to the house, so I assume that the wood is gaining an unacceptably high moisture content in the workshop.

    This type of garage construction is pretty common in the UK, so I assume other people have the same issue as me. My question is – can I do anything about it? I keep the outside walls painted with good outdoor masonry paint to keep them waterproof and the roof is actually solid concrete as there is another garage above (we live on a sloping road!)

    Is it just a matter of ventilation? Or do I need to do something to the walls in side? I was wondering about dry lining them, but would that actually help? Plus I dont want to reduce the size of an already small garage too much!

    I would be interested in what other people do. I am sick of my hard work warping when I bring it in the house!

    Thanks all,


    Chris - Exeter, UK

    • This topic was modified 6 years, 8 months ago by Chris Bunney.

    The problem is air conditioning. You need to condition the air. Do you heat the space? The only other way is to use a Dehumidifier. But either things: Heat or Dehumidifier will have to run all the time. There is really nothing you can do the the walls. Dampness/humidity will flow thru the walls or up thru the ground.

    Located in Honeoye Falls NY USA. The Finger Lakes region of Western NY.

    "If you give me 6 hours to fell a tree, I will take the first 4 to sharpen my axe" Abe Lincoln


    When it rains, does water collect on the ground near the structure, or does it flow away? Are there white marks on the walls (efflorescence)? This could look like white patches or even a crust of white sandy material on the walls. Or, do you see dark, damp spots on the walls at times? Making sure that there is good grading around the structure to carry water away or redirect water flowing towards the structure can help. Even if you end up with air conditioning, if those problems exist, it will mean more moisture for the AC to remove. Look up information about checking and correcting grading around structures and see if any of it applies to you.


    The typical advice is to bring the wood into the house some weeks before use, to allow it to acclimatise.

    Unless you’re made of money it is impractical to keep a workshop as well-heated as a house if it’s only in occasional use. Dry lining and insulation will probably reduce the problem but not eliminate it.


    Southampton, UK

    Chris Bunney

    Thanks for the replies all.

    I don’t air condition the space at the moment (I am considering buying one though) and the only heating is a small 120W tube heater (which pretty much does nothing!)

    I think air conditioning will help, but like Matt says it is not feasible to run it all the time.

    I was hoping that dry lining would be a solution, but I dont want to spend a lot of time and money doing it if it does not solve the problem. I do store some wood in the house at the moment, but it is not really an ideal solution – especially as we have a baby on the way who will take priority on the space (and probably time too, which will make the whole problem moot!) 🙂

    Oddly, I had a similar setup in my old house and I didn’t seem to suffer with humidity so much. There is no efflorescence on the walls, but I don wonder if the floor scree is allowing some damp through.

    I have a horrible feeling that I might be fighting a loosing battle!

    Oh for a nice big, dry workshop or basement like people have in the US! UK style single block garages just don’t cut the mustard!

    Chris - Exeter, UK

    Thomas Angle

    I live in Tennessee and it can be really humid here in the summer months. Actually, I find it humid here a lot. I have a pole barn style garage with vinyl siding back with OSB. There is a too vent and so I have decent ventilation.

    Our home has a walkout basement that has dirt around about a 1/3 of the walls. We have a humidity problem there. In the summer we often have to run a dehumidifier in the basement.

    I would try some ventilation first. If not they make dehumidifiers with gauges that only run the humidity reaches certain percentage. That way it does not run all the time.

    Arbovale, WV

    Proverbs 18:13
    13 He that answereth a matter before he heareth it, it is folly and shame unto him.

    Chris Bunney

    Hi Thomas

    I think that adding some sort of ventilation first might be a good idea.

    I was thinking about some sort of low power extractor fan – we have one in our house (in the bathroom) that has a humidity sensor: it ticks over very slowly all the time and speeds up if the humidity level rises.

    My only concern is that by venting the air from inside, I might be drawing more potentially damp air in from outside.

    I love working with wood, but I do find its sensitivity to humidity a bit tedious sometime!


    Chris - Exeter, UK

    Thomas Angle

    Please keep us updated. I am interested in any fix you come up with.

    Arbovale, WV

    Proverbs 18:13
    13 He that answereth a matter before he heareth it, it is folly and shame unto him.

    Steve Giles

    I live in Bulgaria where practically every ground floor room in the country is damp. I have just tackled this in my house by installing a ‘French Drain’, making sure there is a rain gutter on the roof, and keeping the outside of the walls uncluttered by foliage etc. As stated above, a dehumidifier will help.

    It’s really just a case of making sure that every time it rains, the water is diverted away from the structure instead of being allowed to puddle or get trapped close to the walls. Also, the outside ground level should never be higher than the floor level.

    Peter Ward has some great YouTube videos on the subject of damp in houses.

    Good luck.

    • This reply was modified 6 years, 4 months ago by Steve Giles.
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