23 replies to this topic

[1984mini25]

mine appears to be a lot drier now I've moved the slabs over 8 inches and dug/turned over all the earth along the side of the garage, even after an all day downpour.

[AndyR]

Thanks for all the suggestions

 

I liked the sound of the liquid tanking - would this require chipping out the tarmac that is already there?

 

I have contacted the maintenance company again, and they are going to look into it further.  As you mentioned i dont want to come up with an uneducated solution and end up pushing the water into the walls and affecting the structure.  Will see what they have to say.  If i get the same answer i will have to call somebody in.

 

Has anybody got experience with tarmac rejuvenators? And would this bring back the oil base of the tarmac and inhibit some of the water movement.  If that is the case it may be a middle ground option.

 

Glad to hear your garage is drying up 1984mini25!  Not envious at all!

[Captain Mainwaring]

  The ground level is a lot lower than I imagined from what you said, and from the amount of water to be honest.  I would say that what I described earlier for this would be overkill given the ground level, but that really is a surprising amount of water.  Do you have access all along the back wall and do you have much room there?  What I would be tempted to do is dig a trench right along the back down to the level of the top of the slab, about 2 feet wide so there is good clearance from the bulk of the soil.  Then along the very edge of this trench, up against the slab, I would dig a further trench only about 6" wide down to the base of the slab (probably 5").  Line this with geotex and fill well with compressed gravel, then wrap the gravel in the rest of the textile to make a parcel.  You could lay slabs on sand down in this trench, leaving fairly chunky spacing between them.  That all should prevent water collecting against the wall.  Along the side I would cut the path slabs away for 8" and dig down to lay tanking plastic up the side of the building from the slab base to ground level.  Then get some of the 8" channel blocks that are made as block paving components and lay those in place of the removed sections of the path to guide water along the path and stop it collecting while keeping a flat path at the current height.  All that should do it BUT you might end up with the ground around the garage getting water logged if it isn't actually being carried away somewhere safe.  Soakaways should be 4m from any buildings really, even garages, because of the problem of water softening the load bearing ground underneath.  There is a surprising amount of water here as I said.  You should get a local surveyor who is familiar with the ground to advise you really, they will often give you spoken advice very cheaply if you don't want a fully written report from them.

 

 

He's got a bridged DPC, horrible mortar that's all spalling away.....Uhm,

But the saving grace is as you say, he can at least see the slab (in that first photo) 

Taking a guess that it has none or limited foundations - then if he can get down to just below the slap level all around and cast ground drain gulley all the way around with a cast retaining wall with a nice grill on top then he may stand a chance of letting the brickwork dry out a bit and reduce the hydrostatic pressure at the slab to brickwork joint......if that doesn't work then about 500 gms of Semtex will cure it...

[Captain Mainwaring]

actually the more I think about it, the more I'm, liking the thought of just diverting it towards my neighbours garden. I'd pmsl just to see his garden shed sink.

Google "riparian rights" hehehehe.....

 

If you can get it dry enough for a while you could asphalt tank it....but it would be cheaper to dig the whole lot out, install a land drain below that slab with peas shingle back fill, the mass fill the lot with concrete on top.

[Captain Mainwaring]

  I would like to suggest a liquid tanking but if you trap the water in the brickwork what is currently an irritation may end up becoming a structural problem that would be your fault and would affect the whole block.  Maybe use a tanking membrane on the walls and floor and render over it on the walls, pouring 4" of 40N concrete or something on the floor over the membrane (once the Tarmac is out).  But even then you might well just be causing more problems in the long run.  You need to let the walls breathe.  Talk to a local surveyor.

 

It's test pit time....tarmac on it's own wouldn't be a suitable load bearing foundation for a garage floor. 

Asphalt tanking is good, but it needs a good subfloor. 

Old engine oil will soften aged tarmac..........though I doubt your carpets will approve....

Edited by Captain Mainwaring, 28 May 2013 - 01:15 PM.

[1984mini25]

Thanks for all the suggestions

 

I liked the sound of the liquid tanking - would this require chipping out the tarmac that is already there?

 

I have contacted the maintenance company again, and they are going to look into it further.  As you mentioned i dont want to come up with an uneducated solution and end up pushing the water into the walls and affecting the structure.  Will see what they have to say.  If i get the same answer i will have to call somebody in.

 

Has anybody got experience with tarmac rejuvenators? And would this bring back the oil base of the tarmac and inhibit some of the water movement.  If that is the case it may be a middle ground option.

 

Glad to hear your garage is drying up 1984mini25!  Not envious at all!

oh yes, just the repointing witch isn't going to be a fun job. As I'm pretty certain than the garages were the final bits to be built with all the crap left overs and more sand than cement mortar. 

[Ethel]

how big's your garage Andy? I you don't mind losing some space you could always build a damp-proof structure inside.

[AndyR]

Unfortunately its only a single garage.  Although it is long at over 7 meters, it is a little too narrow; even for a mini!  The last resort is along the lines of what you are thinking of Ethel, and thats for me to use a Carcoon or an AirChamber.  That protects the car, but not all my tools etc - and lets face it nobody likes lying on a damp floor while working on your car!

 

Andy

[Ethel]

Tip for the tools:

 

If you can blag an old fridge or freezer you'll have an air tight tool chest.