Garage condensation

[Flat 6]

Evening all, been a while.

Mainly because I bought a 200 year old farmhouse a year ago so have been busy getting it to a certain point.

Plenty of outbuildings, one of which is a good sized main garage which is where I will be building up my ‘73T if the bodywork guy ever gets his finger out.

Problem is, there is mad condensation on all inner surfaces. One wall is stone (shared with an old byre beside garage) and other three walls are single layer block. Roof is galvanised corrugated tin, floor is concrete and freshly prepped and painted this summer.

The weather has been variable recently with big swings in temperatures and humidity so it may be that today is the worst combination of cold walls and warm, humid air. Every surface is wet. I’d really like to do something about this before I start to use the garage for the 911. I have a few months to sort.

So, hoping some of you have older properties and have dealt with something like this? I’m thinking solution for the walls would be a new inner wall using insulated blocks with a standard cavity. Or I could ‘clad’ the inside of all four walls with some sort of insulated board on battens? For the roof, I’m thinking replace tin with modern insulated profile. I guess there is nothing to be done with the floor.

In the meantime, do you think more ventilation will do any good? There are no external windows, just a big old pair of hung rolling doors.

Thoughts and advice appreciated!

Cheers,

Al

[markm]

If you are getting that much condensation on the walls something is amis, their must be damp somewhere

If you do an inner skin of block or timber/ insulation, you aren’t solving the problem behind the new skin on the existing walls, so potentially there will still be moisture/ damp there. You really need to figure why you are getting it

Another option would be to insulate directly to the wall with an insulated render as you will be changing the position of the dew point, the point at which the Condensation occurs

One thing for sure though, sounds like you definitely new a dehumidifier in there

[Flat 6]

Thanks Mark, hadn’t appreciated there was such a thing as an insulated render. Must ask the plasterer who’s coming next week.

This garage will not have been built to modern standards. I’d be surprised if there was a damp proof membrane under the concrete floor. I’m wondering if it’s ever going to be useful as a car storage garage. I maybe need to decide whether to spend cash trying to improve it or actually build something new, perhaps in wood.

[hot66]

That roof will be a big part of the problem too. I had a garage like that and had to use a carcoon inside it ( which also was not ideal) … the only solution was to build a new garage from scratch , which for me was a timber one

[Jonny Hart]

Tin roof will always be an issue, damp or no.

[stretch]

There are much better products than insulated renders for creating "warm walls". The renders are mainly used in the restoration of historic timber frame walls in listed buildings where adding thickness is not possible. The UV value gain is minimal and it's super expensive to purchase.

[anglophone1]

A good dehumidifier would prob help?

[Flat 6]

There are much better products than insulated renders for creating "warm walls". The renders are mainly used in the restoration of historic timber frame walls in listed buildings where adding thickness is not possible. The UV value gain is minimal and it's super expensive to purchase.

So what would you recommend please? A

[Flat 6]

A good dehumidifier would prob help?

I’ve put a dehumidifier in there to run for 8 hrs (max setting) so will be interested in outcome. Big space though and sliding doors are long way from sealed so I’m probably fighting against high general humidity here in good ole damp Co. Down!

[RobFrost]

Assuming you have no earth up against the walls outside, most moisture will be coming up through the floor, as there is probably no damp proof course. Then it condenses on any cold surface, so the next problem is your walls are cold.

If you leave wood on the floor or against the walls, e.g. cupboard legs, it will likely rot.

Laying a new floor with a dpm below will stop water coming up, or for a few hundred £ you can get an epoxy dpm to run over the top, then you can screed over the top of that.

If the walls have no damp proof course, damp will rise up the brickwork. Injecting silicone all the way round is the standard fix for that. You can also get chemical sticks which you drill and push into the holes.

Any kind of waterproof lining for the walls is simply going to cause problems trapping the moisture and causing mould and mildew. Best solution is something breathable that improves insulation, thereby making the inner surface warmer and suppressing condensation.

If you're in an area where there's driven rain against the walls, an invisible product can be painted on the brickwork to prevent it being absorbed.

Finally, one of the main causes of damp is faulty gutters and downpipes. Have a good look at them when it's raining and confirm they're working correctly to keep rainwater away from the building. Often they're just blocked with leaves or have a badly adjusted downpipe, with the result that rainwater from the roof runs down the walls. Old buildings have lime mortar which is completely permeable so this will just come straight in.

Sent from my SM-S918B using Tapatalk

[Flat 6]

There may well be earth up against some of the back wall since the field behind is definitely higher, another thing working against this garage…

Walls are single block, would be easy enough the damp proof I expect. Floor has been painted with thick garage floor paint but condensation is forming on the floor on top of paint.

I can post a video of empty garage but this site needs it to be hosted somewhere right?

[sladey]

If you use Tapatalk it makes pics much easier

[stretch]

There are much better products than insulated renders for creating "warm walls". The renders are mainly used in the restoration of historic timber frame walls in listed buildings where adding thickness is not possible. The UV value gain is minimal and it's super expensive to purchase.

So what would you recommend please? A

Without seeing the property my first port of call would be to replace the roof and ignore most of the advice on this post until then. This is going to be your biggest improvement. An insulated panelled roof will solve the issue of all the dripping of condensate onto your car, stuff and the floor surface. Spend your money on the thickest insulated panels you can fit.

My next job would be the floor. Vapour transmission to the underside of your 911 will undo all your hard work. Is the concrete solid floor without any signs of debris or earth etc.? What product did you apply to the concrete.? Was it just a floor paint or was it a 2 part epoxy.? Some 2 part epoxy paints can be an effective DPM. Check the product you used. Apply 2 or 3 coats of an epoxy good quality floor system that will act as the DPM... After these two areas are done you may find there is no need to do anything else. If the Garage in non heated and mainly detached then most air movement through the walls will dry them fairly quickly assuming there are no vapour barriers present preventing moisture from wicking away, Gloss paints, Bitumen etc.

Let us know how you get on.

[Flat 6]

Morning,

The block walls are pretty much dry this morning, perhaps due to 8 hrs of dehumidifier, although there isn’t a huge amount of water in the humidifier tank. The only wall still wet is the original stone wall that backs into a store beside the garage. I might just batten and board that and leave be.

Floor paint is not epoxy, two coats of Leyland floor paint. Seemed to take an age to dry. So a waterproof plastic coating of sorts I guess but not to dpm standards. Presumably if I try to put epoxy on top of the new floor paint it will react and I’ll have a right mess to scrape off!?

So roof is first port of call but that’s not happening until spring time. Not needed for car until then anyway. I do have a lot of tools and equipment in there though so I will start to run a dehumidifier on a timer and see how it goes.

Thanks all,

A

[christaylorsound]

I agree that the roof should be replaced with something 100% waterproof, insulated and air-tight. I would also be tempted to smash out the concrete floor, lay a DPM then celotex or similar and thick screed over that. Do what you can to remove air gaps around the door (brush strips?) and keep the exterior walls as dry as possible as described above. It will still take a few weeks of dehumidifier action but hopefully that will keep it dry in future. Also think about a pedestrian door, every time you open the big sliding doors, all that wet air gets in again!