Damp garage

[Robotsan]

This sounds like a plan..

Damp Garage - Ventilation Options

www.mx5nutz.com

 

[Kieronpollock]

I was thinking about the floors, as I've got a lumpy concrete floor at the moment and I'm assuming that's not good for temperatures. Is putting epoxy resin down like using self levelling compound? I imagine my garage only stays a few degrees above the outside temp.

Check out Resincoat. My garage only stayed a few degrees above outside temp but insulating the roof improved it a bit. The game changer was installing a radiator

 

[Dale]

That's what I asked earlier in the thread as I'd heard the same.



I have a single garage built in the 80s I think. Think it's a single course of bricks with a layer of insulation which is then covered with a layer of plasterboard and the ceiling is the same but with wood. Then I've got a draughty garage door and a thin wood door at the other end which is pretty well sealed.

So would I be best off installing a fan at each end to get the air flowing through it?

That sounds pretty similar to my garage.

I think perhaps quick changes in temperature can cause some damp. The best thing I did was insulate the metal garage doors which helped stabilise the temperature inside. It keeps the temperature from dropping too low and before I did it I think that as the outside air warmed up or when the sun hit the garage door it warmed up the air too quickly and any damp in the air condensed on the very cold surfaces.

Now it stays a fairly even temperature. It’s cold in the winter but not freezing and nice and cool in the summer. I haven’t noticed any damp since.

 

[Dale]

I was thinking about the floors, as I've got a lumpy concrete floor at the moment and I'm assuming that's not good for temperatures. Is putting epoxy resin down like using self levelling compound? I imagine my garage only stays a few degrees above the outside temp.

Mine is fully carpeted which I guess also helps.

 

[Robotsan]

Check out Resincoat. My garage only stayed a few degrees above outside temp but insulating the roof improved it a bit. The game changer was installing a radiator

Thanks, will do. I guess the roof is already insulated - there's a layer of loftwool type stuff about 3 inches thick and then wood panelling over that.

Radiator would be a stretch as the garage isn't connected to the house!

 

[Robotsan]

That sounds pretty similar to my garage.

I think perhaps quick changes in temperature can cause some damp. The best thing I did was insulate the metal garage doors which helped stabilise the temperature inside. It keeps the temperature from dropping too low and before I did it I think that as the outside air warmed up or when the sun hit the garage door it warmed up the air too quickly and any damp in the air condensed on the very cold surfaces.

Now it stays a fairly even temperature. It’s cold in the winter but not freezing and nice and cool in the summer. I haven’t noticed any damp since.

I was considering that too. What did you use to insulate the door?

I've just ordered a Bluetooth hydrostat/thermostat off Amazon so I can see what's happening to the temp and humidity in there all year round

 

[uk66fastback]

After my trouble with garage floors - I epoxy-resined my original concrete one which I’d tried to level with levelling compound, but that gave me an awful finish, and I hated thevred, so I took that all up. Then I painted it with grey epoxy-resin. I hated that too. So I did it in carpet tiles finally - which I should have done originally …

 

[Dale]

I was considering that too. What did you use to insulate the door?

I use polystyrene boards to pack out the door sections then covered the whole back of the door with corrugated plastic sheeting.

Jablite Premium Polystyrene Insulation board (L)1.2m (W)0.45m (T)25mm, Pack of 8 | DIY at B&Q

This premium insulation board from Jablite is the perfect solution for insulating walls, floors, and roofs. With a pack quantity of 8 and dimensions of 1200mm x 450mm x 25mm, it provides coverage of 4.32m². It has a BRE green guide rating of A+ and meets the BS EN 13163 standard.

www.diy.com

Antinox Protective board, (H)2.4m (W)1.2m | DIY at B&Q

Tough & trusted in the trade, Antinox is highly versatile and has the durability to withstand any job. Quick and easy to set up, the trade sheet will provide the highest level of cover to your site.

www.diy.com

 

[candy red]

Hey Dale I love the way you’ve numbed the Jablite very well organised but but I’m spotted a mistake the 2 pieces numbered 11 and 14 ,should be 11 and 12 then you would have 13 and 14 at the bottom love your work though

 

[Crasher76]

a cheap way of determining the garage environment is to place some small raw steel sheet offcuts in each corner and see how it reacts?

 

[MCBladeRun]

a cheap way of determining the garage environment is to place some small raw steel sheet offcuts in each corner and see how it reacts?

I love an experiment

 

[toopy]

I have a single garage built in the 80s I think. Think it's a single course of bricks with a layer of insulation which is then covered with a layer of plasterboard and the ceiling is the same but with wood. Then I've got a draughty garage door and a thin wood door at the other end which is pretty well sealed.

So would I be best off installing a fan at each end to get the air flowing through it?

Mine is 90's built, double length, half pitched roof, bare concrete floor, door at the end into garden, garage door is snug but not sealed, no insulation anywhere.
It has lots in it, ironically no room for the car! and yes it can get rather cold, but i have never had any damp and nothing seems to flash rust. I think because the temp changes slowly there is never any condensation forming, plus the garden door at the end is used on an almost daily basis throughout the year and can often be left open if not too cold or raining.

 

[Robotsan]

I bought a humidistat. It's Bluetooth so I can track humidity and temperature over time too - which should be useful, especially when trying to assess the success of any improvements I make!

Quick alarming stats for the first night though..





Annoyingly the app only reports in Farenheit, but that's gone from about 22°c (must have warmed up in the sun yesterday?) to 10°c at 8am, which is pretty much exactly the outside temp.

More worrying, humidity rose to 92%, which again is exactly what it is outside right now.

So I'm guessing a more sealed and insulated garage wouldn't get as cold and as humid as the outside world?

I've never seen condensation on the car or on anything in there though.

 

[JamMe]

I bought a humidistat. It's Bluetooth so I can track humidity and temperature over time too - which should be useful, especially when trying to assess the success of any improvements I make!

Quick alarming stats for the first night though..

View attachment 61585

View attachment 61586

Annoyingly the app only reports in Farenheit, but that's gone from about 22°c (must have warmed up in the sun yesterday?) to 10°c at 8am, which is pretty much exactly the outside temp.

More worrying, humidity rose to 92%, which again is exactly what it is outside right now.

So I'm guessing a more sealed and insulated garage wouldn't get as cold and as humid as the outside world?

I've never seen condensation on the car or on anything in there though.

@admins - maybe we should move this discussion to its own thread - as this has kind of taken over @Banshee_240Z's thread?

Good device, useful.
Yes, you need to insulate your garage from the outside world so that the internal parameters don't change with the weather outside.

 

[Banshee_240Z]

As a temporary measure I did buy one of little plastic moisture absorbers (We have one in the bathroom too) and it did start filling up a bit with water within the first couple of days. It has since tapered off a bit so I think that would indicate it's doing its job and the garage is sealed well enough.

For 10 quid I figure if it does anything at all I'll be happy! Would be curious to see actual results from your humidistat @Robotsan

Amazon.co.uk

 

[Paul_S]

Yep, I have those in my garage and even keep one in my 370Z because I don't use it too often and the windows can get misted.

They do work well but better if you have moving air.

 

[Stockdale]

Humidity and it relativity to temperature is frequently misunderstood. Essentially condensation will occur where atmospheric humidity exceeds 100%. It can happen within buildings including garages and also in vehicles. Careful maintenance of air temperature against background humidity is really the only protection to condensation and risk of corrosion or other surface damage. Either maintain background air temperature at a level above dewpoint which is itself a variable or mechanically remove excess air moisture in a sealed environment by dehumidification. Otherwise just accept that a degree of corrosion will naturally occur, even in a garage and take steps to minimise its effect. I find that laying old cardboard beneath my cars is quite effective and tends to absorb condensing moisture. It needs to be replaced or at least dried out now and again outside on a dry sunny day.

 

[uk66fastback]

That’s serious condensation if it’ll make cardboard ‘damp’. I don’t have any trouble in mine at all - I’m doing nothing to eleviate it though - it’s just ‘not happening’ as far as I’m aware. (Single, 1990s-built brick garage, d/g side door and window, carpet tiles now, plus insulated roller door …

??

 

[Robotsan]

Humidity and it relativity to temperature is frequently misunderstood. Essentially condensation will occur where atmospheric humidity exceeds 100%. It can happen within buildings including garages and also in vehicles. Careful maintenance of air temperature against background humidity is really the only protection to condensation and risk of corrosion or other surface damage. Either maintain background air temperature at a level above dewpoint which is itself a variable or mechanically remove excess air moisture in a sealed environment by dehumidification. Otherwise just accept that a degree of corrosion will naturally occur, even in a garage and take steps to minimise its effect. I find that laying old cardboard beneath my cars is quite effective and tends to absorb condensing moisture. It needs to be replaced or at least dried out now and again outside on a dry sunny day.

So it's only when there's condensation on things that they'll rust? I was under the misconception that it was just if the air was humid enough, things will rust. But it has to actually condensate onto the surface?

So the options are either heat the garage, or dumidify the garage? I guess then it comes down to which is cheaper.

I've got cardboard under the car too, but that's mainly to catch all the oil

When my car goes for paint in September I'm going to put a new floor down, and insulate the doors etc. Might end up buying a carcoon in the end tbh.

 

[yellowz]

So it's only when there's condensation on things that they'll rust? I was under the misconception that it was just if the air was humid enough, things will rust. But it has to actually condensate onto the surface?

I always thought if the metal was colder than ambient humid air that would be sufficient to cause condensation = conditions for rust