Garage Tanking Issue

Discussion in 'Builders' Talk' started by GarageGym, Feb 17, 2021.

  1. GarageGym

    GarageGym New Member

    Hi People,

    We have a newly built garage back in the summer image below.

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    When winter came...rain came! Basically the under side of the roof started growing mould on it, we noticed the bricks were quite saturated with water

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    It's a single skin built garage.

    So I did a bit of research online.... Found that TANKING was the solution. So we bought 2 buckets of KA Tanking Slurry.

    Applied the first coat (White)

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    then within 24 hours the 2nd Coat (grey) and a 3rd coat to make sure.

    This was 3 weeks ago now....

    We are still seeing water coming through. Some parts have dried, but we still have a lot of water beading on the bricks.

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    Question is... Has it failed or was it no applied right?

    I'm at a loss. When I think it's started drying, and it's light grey. But after some rain it starts coming through again. The light grey bits are dry.

    But it's been nearly a month. Is this normal?
     
  2. warcs

    warcs Member

    looking at the first picture the garage is build quite a long way below groundlevel around the sides. If so did you apply any tanking to the external face of the wall?

    I mean is the ground pressed against the wall?
     
  3. GarageGym

    GarageGym New Member

    There is a garden to the right. They did put pebbles between the soil and the garage for drainage. I was also told they did a wall then do the brickwork, but I wasn't there I was at work. I cannot access the outside of the right side since the neighbour garage is right next to it. there is no space for me to get into to apply anything on their outside of the garage.

    there isn't any tanking on the outside. this was a while after. i read about tanking can be applied in the internal wall to stop damp coming though and the water would remind in the brick from the outside.
     
  4. warcs

    warcs Member

    Is the water coming through all 3 walls? when you build a structure below ground you should tank the outside with a proper waterproof membrane. It looks from the pictures that it is a single skin of blockwork with a small wall around the sides of your garden giving a gap between the 2 walls which have been filled with pebbles, with the amount of rain lately i would imagine the pebbles will be full of water as it cant drain away. The low wall is only preventing the soil from pressing against the wall but doing nothing to stop rain water from filling up the gap and then sitting against it. Painting the inside with something isnt an ideal solution as you have found and very often fails unless you use the correct product. There is a company called SIKA which produce products that will fix to the inside of the walls and may well be ok, they are the go to people to sort leaky basements. There maybe others that do a similar render but i dont know of any. have a look at their sika render
     
  5. GarageGym

    GarageGym New Member



    do mean something like this?, isn't this what tanking slurry i applied already does? Do you think it might be worth doing another THICK layer of slurry on the existing one iv'e done? When we had a few days of no rain last week the walls were fine and the slurry was drying out.

    We have a few days of 18 degrees coming up soon. I think the slurry hasnt had time to actually cure properly. as the very light grey parts are dry.

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  6. warcs

    warcs Member

    no look for sika render, but give them a call as they are the experts to your problem
     
  7. GarageGym

    GarageGym New Member

    So the tanking we done is useless?
     
  8. glob@l

    glob@l Active Member

    I believe the KA Tanking is applied to wet surfaces and so crystallises on contact. Two coats are advised 1st coat paint strokes one way then 2nd paint strokes at 90 degrees to the 1st.
     
  9. GarageGym

    GarageGym New Member

    Yes I dampened the wall too before doing the coats. I did 3 coats... diagonal then vertical
     
  10. koolpc

    koolpc Screwfix Select

    The water is not getting in from above?
     
  11. GarageGym

    GarageGym New Member

    nope,

    it's basically the water from outside getting rained on the brick soaking it in, and it's seeping through to the inside in droplets. The roof is dry. Some part of the walls are completely dry like the higher up bricks.
     
  12. Okoak

    Okoak Active Member

    I'm sorry to say, but that is never going to be watertight, it's a complete cock up from start to finish. Painting stuff on the inside of the walls and hoping for a result is like wearing a raincoat in a leaking shower and hoping it will stop the water leaking past the defective silicone sealant.
     
  13. GarageGym

    GarageGym New Member

    Thanks.

    But tanking is what it's for when you can't get to the outer walls. It's been built now can't go back in time can I.

    Wall tanking or “tanking” is a method of preventing water ingress by creating a completely impermeable waterproof barrier on an internal wall. When we refer to tanking walls, it's usually in reference to below ground structures like basements or as a precautionary measure on damp walls above ground. The term “tanking” comes from the idea that by completely sealing a room, a waterproof tank-like barrier is created.

    What am asking is it's supposed to do what it's made for. So what went wrong? Not thick enough? Not enough time to cure?
     
  14. GarageGym

    GarageGym New Member

    Ok so there's a brick wall between the left side of the garden soil then pebbles then the garage was built. It's not against the garden surface to surface.

    The right side is full exposed although very very close to the neighbours garage. I guess the tanking has failed or isn't thick enough.

    Also some salt deposits are visible on the inside
     
  15. koolpc

    koolpc Screwfix Select

    Which side is letting water in? Left or right as you look at the garage from the front.
     
  16. GarageGym

    GarageGym New Member

    Both sides and back. More the exposed side on the right though. The back at the top is dry
     

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