Rain water coming through sectional garage

Hi,

I have one of those old sectional compton/lidget garages and I've noticed rain water is seeping through inside. I can't see any leaks on the roof but from outside I think the rain water is seeping through under the concrete panels and between the joints (see attached pics) where the mortar has come lose and where the bottom edges of the panels have deteriorated to the extent you can stick your finger through.

How do I fix this? I've been googling around and I've come across a few post where people are advising to put a sand cement fillet around the outside. I'm not great at mixing sand cement so is there some ready mix sand/cement I could use. Is this stuff suitable: https://www.screwfix.com/p/cementone-waterproof-cement-grey-10kg/58196 or this: https://www.bostik.com/UK/products/Cementone-Wide-Jointing-Compound or would you guys recommend something else i.e bag of sand cement and mix it by hand?

Also what is this mortar used between the panels - is it general purpose mortar or some kind of special sealant and where can I get some from - a brand recommendation would be appreciated?

Finally some of the concrete panels are cracking/damaged from inside - see attached pics. Can these be patched up with the same sand cement mix used for the fillet?

Any tips, step by step instructions advice will be much appreciated on how to to go about repairing this garage.

Thanks.

Until I replaced mine I just accepted they leak like sieves .

I had good results with a decent sized fillet of 4:1 sharp sand and cement with the area primed with an SBR/cement slurry. It went from the floor being awash with water (partly as it's built into sloping ground so the floor is below the external ground level in places) to bone dry for years - even with the current rainfall. The same slurry can be used to prime the spalled panels before patching with building sand/cement at 4:1. To reseal the panels I would rake out a bit - not too deep, and reseal with PU adhesive (comes in a tube like silicone) from Toolstation.

i dont like S&C fillets but what you've done is impressive.

cdbe said:

I had good results with a decent sized fillet of 4:1 sharp sand and cement with the area primed with an SBR/cement slurry. It went from the floor being awash with water (partly as it's built into sloping ground so the floor is below the external ground level in places) to bone dry for years - even with the current rainfall. The same slurry can be used to prime the spalled panels before patching with building sand/cement at 4:1. To reseal the panels I would rake out a bit - not too deep, and reseal with PU adhesive (comes in a tube like silicone) from Toolstation.
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Hi,

Thanks for the tips.

Is this stuff adequate to re-seal the joints between panels https://www.screwfix.com/p/sika-sikaflex-ebt-all-weather-sealant-grey-300ml/79250 as I can't seem to find any grey PU adhesive from toolstation. Otherwise I could apply this Puraflex product which is cheaper https://www.toolstation.com/puraflex-40-high-modulus-pu-sealant-adhesive-300ml/p67949 but comes in white.

Also do you apply the adhesive from outside or from inside?

I've used the puraflex before, it will do the job - there may well be other exterior sealants that will work as well - a polite email to Compton themselves might help.
I would reseal from the outside, try and mask up, practice on an unseen area as the stuff is sticky and messy.