HELP!? Keeping A 1970's Single Garage Dry?

[Crispy1989]

Hi All!

First time post but have been a long time reader of the forum. I bought my first property in 2020 which is a 1970's maisonette which includes a single garage which is one of the middle garages in a row of 4.

Last winter and whenever there is heavy rainfall the garage becomes damp as small amounts of water/damp appears on the floor. I'm looking to use the space as a home gym/storage so I just need it to be kept dry without ruining everything kept in there.

The construction of the garage is concrete floor (without dpm), single skin brickwork walls which have a dpc (noticeable in images) and big 6 asbestos roofing on timber joists with full width double timber doors on the entrance. The ground at the front of the garage is mostly concrete/gravel and is slightly higher than the height of the garage floor, however just before the garage the ground is soil (as noticeable in image).

1. I'm unsure BUT using a combination of dpm or tanking/paint, floor insulation boards and/or concrete screed on the floor to bring the finished floor and dpm above the level of the ground outside and the bricks dpc would significantly help keep the floor dry??
2. In addition perhaps boarding/insulating in between the timber joists on the ceiling to cover the asbestos ceiling would also help?
3. I'm reluctant to stud/board out the walls as i'd like to keep involvement/cost to a minimum.

I'd really welcome any advice on the correct way how to best construct the floor/ceiling build up to make the garage a dry useable space.

Thanks!

 

[Harry Bloomfield]

Lay a membrane to cover the floor completely then concrete or screed over that to 150mm. A cheaper way, might be a membrane with joists and new floor built on top, but it depends on how much you want to spend/want it to last. You would need to leave some clear space around the edge, so as not to bridge the DPC, polystyrene strip will help with that, if laying concrete/screed.

 

[mattylad]

Also consider an internal front wall and door, that may help keep out any water from the garage looking doors.
Sort the roofing out too, check for any leaks.
when doing the ceiling how about having it so that any water coming through drains somewhere.

 

[noseall]

It's pretty low end structure so any improvements are going to be costly. I'd avoid timber floor joists for risk of mould and rot, but the theory of creating a membrane protected/insulated 'cell' within the garage space, is sensible.

 

[Crispy1989]

Hi All, thanks for you responses, really appreciated.

On the basis of what youve said i think im going to brick up to dpc height on the front entrance and the pour a 2 part liquid dpm over the existing floor and paint up/join to the dpc. My hope is this will create a miniature basement like system where moisture can no longer get to the floor - i think this is what a couple of you are advising....i hope

The ceiling is sloped so i should be able to find a way to direct water away under the front of the roof. Does anyone think either or both of the following are a good idea:
1. Boarding between the joists with ply/osb so i dont have to look at a miserably damp ceiling? Or does this create more problems with the condensation?
2. Installing air bricks? the garage isnt exactly airtight anyway so seems a little pointless?

Thanks again everyone!

 

[Tigercubrider]

depends on how long you intend to stay there.
what you are doing may turn off future buyers so consider making any changes removable.
You could fit plastic based decking supports over a liquid dpm and insulate between, decking with ply or chipboard.
no point unless you are sure the water doesn't come from above

 

[catlad]

Have you considered the wallbarn products with flags on top? that should give you a dry base.

 

[Crispy1989]

I do like the decking feet systems and the idea of a raised floor, but since i'm using this as a home gym and dont want to spend unnecessarily i'll most likely just buy thick rubber tiles and lay these ontop of the liquid DPM (Ardex DPM1C). That'll be fine right?

I intend on living here for another year or two. Honestly anything i do to this garage cant make it worse than it already is and i just want to be able to work out and get healthy in it rather than risking getting ill from it being damp lol!

I'm pretty sure these droplets are from condensation rather than from a porous/leaky roof?! Fixing the floor would help this right?
Take a look at a picture of the sloping asbestos roof.

 

[Mr Chibs]

Is it definitely asbestos?

The profile looks a little small for Big 6.

I was under the assumption, that asbestos is it dimpled on the underside of the sheet?
I know mine are.

Sorting the floor will not stop condensation on the roof.

 

[Crispy1989]

Yeah pretty sure its big 6 asbestos.

Have you got any ideas how to solve the condensation?

Thanks

 

[Mr Chibs]

Spray foam, stops it, but you’ll need someone to apply it.

Doubt it’s worth the cost.

Can you add a secondary ceiling, is there anything you can screw a framework into... joists etc.
I’m thinking of using celotex pushed to the asbestos, as I’ve got good airflow at the ends.

Food for thought.