[kevinephraim]

Hi guys,
Was going through the off beat section of T-Bhp and realised that there was no Home Improvement section here.

I have the waterproofing of my house being carried out presently and thought i'd give fellow BHPians an idea of how its done.

This may not be the only way to do it or "THE BEST" way to do it etc. but its the way it is being done at my house.

All comments and suggestions are of course welcome and requested.

MODs : Kindly advise if this is the wrong place for this thread.

Am attaching some initial Photographs of how my roof looked like and the actual condition which warranted waterproofing to be carried out again.

The first few Photos show what the builder had given when he sold the house.

This is a Row House and the area seen is the top most terrace / roof area. House is presently 7 yrs old and NIL leakages / seepages were found till the very heavy rains earlier this year 2010. It had been tiled with terracotta tiles and the tiling was done with minimal gaps and good cement filling between each tile.

Have attached some Photos of the seepage finally seen after 7 yrs. Presume this happened because the harsh rains and carbonic acid action in rain water eroded the cement filling between the tiles.

As the photos show: The Concrete slab was layered only with 2 to 3 inches of sand and the tiling carried out on top of this.
For all out there.. This is a short cut method used by the unscrupulous builder to save money and must never be carried out!

[pvgeorge]

My present house also started leaking after at some place. After all its same as my age (33 yrs). I wasnt sure on the water proofing methods and decided to put aluminium sheets over the terrace (so that no water falls in terrace). Cost : 1.4L for 1450 sqft.

But got lot of advantages like
- Full terrace availability for dumping
- Never did I switch on the AC after that (it realy reduces the temp inside the house)
- a good space for a get together

[kevinephraim]

Originally Posted by pvgeorge

My present house also started leaking after at some place. After all its same as my age (33 yrs). I wasnt sure on the water proofing methods and decided to put aluminium sheets over the terrace (so that no water falls in terrace). Cost : 1.4L for 1450 sqft.

But got lot of advantages like
- Full terrace availability for dumping
- Never did I switch on the AC after that (it realy reduces the temp inside the house)
- a good space for a get together

Putting aluminium sheets will help greatly, as you have said, in not allowing any water on the terrace during rains and also gives the 3 advantages that you have stated, however i think that Good waterproofing is still required for any house to remain structurally sound.

33 yrs has shown that your construction was very good and spending a bit more again should increase the life and resale value of your property.

Originally Posted by pvgeorge

- Never did I switch on the AC after that (it realy reduces the temp inside the house)

As seen from my photos, there was absolutely no brickbat work done initially by my builder, therefore the heat during summer was unbearable as all the heat was directly transferred to the room below. As you will see in the next few posts when this in progress, we will be completely removing the tiles and laying a brickbat layer. This will greatly reduce the heat transmission by upto 65 % to the slab and thereon to the rooms below.

The person i am getting it done from is charging me 80k for 1000 sq ft. which includes removal of all old tiling and sand, cleaning the slab, laying of waterproofing mixture, laying of brickbat and final cement top layer.

[Aroy]

Beware of leaks. The leak can start at one place, propagate through cracks in the masonry and exit at some other place. The best method is to use water proofing compound which commercial waterproofing contractors use.

For roofs they spray the compound, and if any cracks are visible force the compound using a pressure pump. Another method popular in Delhi is to have "foam concrete" of some 300mm thickness laid over the roof slab. This would not only seal the roof but also provide insulation.

By the way, it is better for the leaks to dry out thoroughly before sealing, otherwise the the moisture in the walls will keep on surfacing for years!

[AWD]

We are facing the same problem in our ~35yrs old house. The floor of the roof has developed cracks & holes through which water seeps in. Earlier the same thing occured in another of our premisis. We got the corners filled with concrete & cracks/holes filled too. The problem was taken care off.

For the new problem, a contractor advised to re-teep the roof. This would cost too much because the roof floor area is large. So, we will apply the same solution as earlier i.e. get the cracks & corners filled with concrete.

@Aroy, the compound spray sounds good, what sort of costs are involved & is the solution permanent?

[Aroy]

Originally Posted by AWD

We are facing the same problem in our ~35yrs old house. The floor of the roof has developed cracks & holes through which water seeps in. Earlier the same thing occured in another of our premisis. We got the corners filled with concrete & cracks/holes filled too. The problem was taken care off.

For the new problem, a contractor advised to re-teep the roof. This would cost too much because the roof floor area is large. So, we will apply the same solution as earlier i.e. get the cracks & corners filled with concrete.

@Aroy, the compound spray sounds good, what sort of costs are involved & is the solution permanent?

Please contact them Cico Group- India, Construction, Chemicals, Waterproofing, Compounds
Get them to seal all the cracks and then cover the roof with cement slurry.

I would still advise you to redo the roof surface, as that would solve your problem long term. You can strip the roof of all tiles and re-use them only adding new tiles where necessary.

[srishiva]

Sand between the tiles and roof was a real bad idea I guess. If at all any water seeps in, it will be held and distributed across easily. Also, if the tiles transfer any heat to the sand, you will have a hot/warm roof all night long.

I think there are some light weight, heat resistant tiling materials available. But again, the problem is with making sure they are held tight to avoid any water seeping in.

Painting the roof white might be good especially for hot climate.

[kevinephraim]

Updates..

The tiles were all removed and so was all the old sand that the builder had used. the entire slab was cleaned out thoroughly and dried in the sun for half a day (as long as it takes to dry completely)

Then a slurry consisting of cement mixed with Mr. Fixits URP waterproofing compound was layered on the existing slab. This layer has to be done at a single go while the slurry is liquid all over the roof as this is the first and main layer of waterproofing. Its always better to start this in the morning if you have a large terrace / roof like mine as it will be difficult to finish the entire are through the day if you start later. The slurry must be a minimum of 1.5 cm thick. This must be layered on the sides of the adjoining walls and in corners upto a height equal to 3.0 cm greater than that of a flat lying brick. This is to permanently block any water that may seep through the wall during curing.

[Guite]

Kevin,

If you have not covered up (finished)your terrace yet, you can consider laying extruded polystyrene insulation boards. This will shoot up your cost but will give you very good thermal insulation. Its a light weight material like thermocol, but don't try using thermocol.

Guite

[kevinephraim]

Originally Posted by Guite

Kevin,

If you have not covered up (finished)your terrace yet, you can consider laying extruded polystyrene insulation boards. This will shoot up your cost but will give you very good thermal insulation. Its a light weight material like thermocol, but don't try using thermocol.

Guite

Dear Guite,

Thanks for the suggestion, however the roof is done and i will be posting the last few updates soon.

I had this suggestion of Polystyrene boards to reduce the heat before i started the waterproofing, but it was to be layered inside the room with a false POP ceiling done with lighting etc.

Since i now know that there was no brickbat layer initially and now i have got it done, i intended to wait till the summers to see if the brickbat will reduce the heat or not. Else will be going in for the polystyrene layer with a POP false ceiling.

Keep watching this space for the final set of updates and Pics.

[Sn1p3r]

Kindly forgive my lack of understanding/imagination but how were the aluminum sheets used to be effective and secondly how will polystyrene sheets used to cut heat inside the room.

I have to redo the ceiling for my place as well. Heat on the top floor is a killer in Gurgaon.

Thanks!

[pradipk]

Originally Posted by Guite

Kevin,

Its a light weight material like thermocol, but don't try using thermocol.

Guite

Hey what's the issue with thermocol? I mean why that can't be used?

Thanks.

[kevinephraim]

Originally Posted by Sn1p3r

Kindly forgive my lack of understanding/imagination but how were the aluminum sheets used to be effective and secondly how will polystyrene sheets used to cut heat inside the room.

I have to redo the ceiling for my place as well. Heat on the top floor is a killer in Gurgaon.

Thanks!

hey Sn1p3r,

The aluminum sheets were used as the top on a framing to create a shed type area. that would reduce the direct heat hitting the concrete slab.

The polystyrene sheets are like thermocole, therefore having heavy insulation properties, i do not know how they can be used on the top of the terrace, while i do know that they can be incorporated inside an aluminum framing and false ceiling to reduce the effect of the heat penetration into the room from the concrete slab.

[Guite]

Extruded polysterene (XPS) and thermocole are in reality two totally different materials, both physically and chemically. There are XPS boards specially designed for terrace application which can take the load of people walking on top of it. Just try walking on thermocole sheet. And remember you will be applying mortar and some tile finish, etc on top of it. When the thermocole gives way, the top finish will crack. Moreover thermocole may not behave very well in cyclical hot cold cycles.

There is a big advantage in putting insulation on top of slab because you are stoping heat and cold before it gets in.

[Thad E Ginathom]

We have the heat-resistant/waterproofing white paint applied to our terrace, which was just plain cement.

First, the heat-resistant angle: it is noticeable. Of course, any white paint would help with this.

Second, the waterproofing. We had a lot of leaks before, and very little since. the trouble is that there are cracks in the concrete and, although they apply silicon sealant to these, it is not a permanent cure, and has to be reapplied. Of course, if once there are cracks in concrete, there always seem to be more, so any paint surface is going to be subject to breaking.

There are membrane systems, coupled with epoxy paints, which are sold as being very durable, and they might be a cure to a terrace which already has cracks. They are much more expensive.

However much money we were to spend on the surface, and that can't really be done at this time, I would always want a white, heat-reflective surface.

The aluminium sheets would be great, and I've often been tempted. One could even put net at the sides for a mossie-free roof garden. But we have a solar water heater.