Sealing a new flat roof top terrace against the elements

[olive]

Does anyone know what (if anything) is done to seal a flat roof terrace?

A friend is having a new flat roof (traditional concrete beams, bovadillas then concrete laid on top with mallazo wire grid reinforcement) Then the builder appears to be going to lay suitable outdoor tiles and upstands on top of that with a slight fall and drains at the edge. It maybe that he is going to do something else e.g. a waterproof membrane somewhere but that may have got lost in the translation.

Has anyone had a similar thing done? Is it just water resistant tile adhesive!

olive

[Grouser]

Normally the concrete is painted with a red latex sealing paint. I'm afraid I don't have a product name. This must be done with several coats and very carefully so as not to leave the slightest hole. The tiles are then laid on top. In our case they were not careful enough with the sealant and we have had to seal the tiles with a waterproofer. This is not satisfactory as traffic wears through it and it has to be re-sealed every year.

[campo babe]

Yes, our roof terrace, and another terrace which has a room underneath has a waterproof membrane underneath the tiles. Sorry don't know the name.

This is OK as long as you know it is there. For example you cannot fix anything to the tiles if it is going to go through the tiles and into the membrane, i.e. posts for a gazebo etc. This would then make a way through the membrane for rain etc. and into the underneath rooms.

[El Cid]

Our flat roof had a bitumen layer. It came in rolls about 1m wide and the overlaps were was joined with a blowtorch. This was then cemented over.

A couple of coats of "Gaucho" can be used if you want to seal a leaky roof - it's a rubber based paint also known as Impermearbizilante.

Rugoplast is a brand and it comes in red or white.

Sid

[spanish_lad]

sealer paint comes in three colours that i´ve seen so far, red, white and black. its very sticky, very thick, and you will need lots of it

normally a builder will spray the roof with a yellow "spray foam" type substance - thats what they seem to use now as a waterproofer.

i´ve worked on roofs where nothing is used, but they are generally more sloping.

yes, you can fix a gazebo or something to the roof, as long as you seal the holes with PLENTY of silicone sealer.

[nevada smith]

he'll probably use
tela asfaltica (a tar-like sheeting)
or one of the new laminated PVC foils
(both are effective)...
depending on how hot the roof gets & whether there is a bedroom below -
your friend might want to consider insulation...
we always put down at least 5cm of DOW styropor roof panels
then the tela or the foil...

[MarkF]

I do this sort of thing for a living, our product is suitable. Take a look at my site and try and find some locally. I get loads of enquiries from ex-pats in Spain and France but it's heavy (1.5 kg per sq.M) an uneconomical to send from the UK.

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[campo babe]

Thanks spanish_lad for the info about using Silicone to seal the holes when fixing something to the roof. I will have to see if I can persuade my husband that we can now have some shade on our roof terrace!

[olive]

Many thanks for all your replies. I have passed these on to Bob.

olive

[AndyLucyOne]

What is the recommended finished-fall for a tiled flat roof terrace in Andalucia, to cope with the peak rainfall ?