Roof Leakage: Preventative Measures

[gch555]

Where there is evidence of water problems in your ceiling, what is directly above it? Any water pipes (either supply or waste pipes)? Try and marry up water damage with a potential source directly above, if possible.

I think hold off for a bit and keep an eye on it for the next couple of weeks. Because it's such dry weather, if it gets worse without rain then it's likely not rain damage, it could be a water pipe above. If you want to confirm, look into fluorescent water tracing dye, which you dilute in water and pour down the drain. If you see the dye coming through the paint in the ceiling (with a UV light is better) then it's a piping problem not waterproofing. Any stains on the ceiling from the dye isn't a problem, you'll be painting anyway. You may even discover another issue spot that isn't visible to the naked eye (yet).

DIY waterproofing isn't a hard job, but choose the right one. Most don't like heavy foot traffic, some don't like UV exposure and alot don't like water ponding on top of it (accelerates degradation). It's the best time of year to do it anyway. Brands like Kangaroo or Sika are popular in HK, a 20L bucket is about $1k and should be good for a few coats of non-trafficed areas of your roof.

If it were my place, I'd start with:
- clean drains
- pressure wash the whole roof so you can see the surface better. Most handymen would have one, if not a painter. Need to clean the surface prior to applying any sealants/waterproofing anyway otherwise it'll peel off like skin on a soup
- check surface for cracks or damaged paint/sealants, check water pipes and seals for leaks
- soak the roof and look for spots water ponds. Ponding is never good for any waterproofing membrane
- consider a paint on waterproofing membrane (sika/kangaroo as above) around low points, wall-to-floor joints, around drains
- consider a waterproof tile grout and reapply if existing grout is old/chipped

Now's the time to get it right, the weather is great for it. Much more of a pain when it starts raining and you realise you missed a spot!

[rook_hk]

GCH, Awesome tips, man.

Thank you!

[imparanoic]

a roof like, waterproofing paint/cover won't stick to the blackened tiles and badly worn out grout.

if i was you, i get a contractor and use bitumen which needs to be heated and that stick to anything and it's water proof, that's the simplest way

[imparanoic]

瀝青 (lik ching) is the chinese name of bitumen, it's what use on the roads but add aggragate/stones, need to be heated.

on the other hand, apparently you can get bitumen paint and use that, apparantly no need to heat up, please see link below

https://www.5metal.com.hk/content/%E...-bitumen-paint

[imparanoic]

Where there is evidence of water problems in your ceiling, what is directly above it? Any water pipes (either supply or waste pipes)? Try and marry up water damage with a potential source directly above, if possible.

I think hold off for a bit and keep an eye on it for the next couple of weeks. Because it's such dry weather, if it gets worse without rain then it's likely not rain damage, it could be a water pipe above. If you want to confirm, look into fluorescent water tracing dye, which you dilute in water and pour down the drain. If you see the dye coming through the paint in the ceiling (with a UV light is better) then it's a piping problem not waterproofing. Any stains on the ceiling from the dye isn't a problem, you'll be painting anyway. You may even discover another issue spot that isn't visible to the naked eye (yet).

DIY waterproofing isn't a hard job, but choose the right one. Most don't like heavy foot traffic, some don't like UV exposure and alot don't like water ponding on top of it (accelerates degradation). It's the best time of year to do it anyway. Brands like Kangaroo or Sika are popular in HK, a 20L bucket is about $1k and should be good for a few coats of non-trafficed areas of your roof.

If it were my place, I'd start with:
- clean drains
- pressure wash the whole roof so you can see the surface better. Most handymen would have one, if not a painter. Need to clean the surface prior to applying any sealants/waterproofing anyway otherwise it'll peel off like skin on a soup
- check surface for cracks or damaged paint/sealants, check water pipes and seals for leaks
- soak the roof and look for spots water ponds. Ponding is never good for any waterproofing membrane
- consider a paint on waterproofing membrane (sika/kangaroo as above) around low points, wall-to-floor joints, around drains
- consider a waterproof tile grout and reapply if existing grout is old/chipped

Now's the time to get it right, the weather is great for it. Much more of a pain when it starts raining and you realise you missed a spot!

that's a lot of man (ten's) hours work, especially for a place the op don't own.

[gch555]

Bitumen is another option but a black roof will likely make your apartment feel hotter in summer. Be sure that the option you use is both UV resistant and trafficable. Walking directly on some membranes will feel 'sticky' in summer as a result of their elastic properties so can sometimes peel off with foot traffic. This is why some products need to be underneath tiles/screed or other layer to protect the waterproof membrane.

Waterproofing my roof about the same size was $18k including some new screed to correct the fall to the drain, using a kangaroo product. This is almost 2 months rent so it's up to OP to decide how much his time is worth and how much he likes DIY. I appreciate DIY isn't for everyone but understanding the problem with some investigation will help whoever does the work, OP or a contractor. Why pay for the roof wateproofing if it turns out to be a leaking pipe? Old building, could be lots of things...

[Geraldo]

Excellent advice from GCH - we have a similar roof and more or less do the same using Sika products. It's not difficult and we're simply resigned to re-doing it(or, rather, our housekeeper is!) every other year or so. You can buy all the stuff in what we call 'leak street' - 1118 Canton Road. If your place is near Mongkok and need to employ someone to do the job we know a very experienced person!

[East_coast]

Remove the grout with a multitool



Regrout with concrete using a bonding agent



then a few waterproofing layers layers topped with hard epoxy paint



https://www.youtube.com/watch?v=WJPMvI4hv_Q

http://ardex.com.hk/product/ardex-wpm-300/