hi ! calling all roofing sifus out there, nowdays roofing contractors will recommend that you put a foil sheet underlay to help with heat reduction and acts as a second layer barrier to prevent leaks.

lets say one does a full roof change and added this foil sheet. what would be the best way to identify if there are any leaks and check whether the roof was installed well with no leaks? can't seem to identify the areas with leaks due to the foil covering.

thank you.

Depend on foil material, else it is very minimal for heat reduction. And it is no way to help to prevent leakage. Please get the right information before further your roof work.

hmm ok. so for those people who have foil material underlay, how do you determine if there is a leak in your roof since it will just flow down the foil layer?

It is very hard to determine the leaking point.

Purpose of the foil layer is to reduce roofing heat and prevent small leakages from going further inside your house. Engage a pro-roofer to do a detailed go through and not those with limited knowledge of roofing.

Can i ask? Is it a metal roof or tiles roof?

Usually metal roof, then alu foil is insufficient. You will need insulation material like glass or stone fibre (some comes together with PU).

If a tiles roof, what it does is to increase the heat resistance value. If you are planning to put woven foil, i doubt it will have any benefits that will create impact. However, if is a bubble woven.foil, if does help. Just google - roofing insulation or search under Monier tiles roof system.

And confirm.. if there is a leakages... u wont be able to determine it. Its applies for both types of roof.

Hope this helps.

This post has been edited by stanck: May 18 2020, 03:34 PM

And my contractor told me they will put zinc sheet underneath the clay roof tiles then only foil sheet. The zinc sheet supposely to prevent leakages. Legit? Of cos they will patch back all leaks while doing so.

Zinc sheet plus foil sheet is high spec set up, even foil sheet will help prevent leaks if the overlapping is done well. Of course if u can afford it better lor zinc sheet. The biggest problem with underlayment is that If a contractor does a bad job installing your roof as u would never notice leaks until your underlayment gives way.

Roof tiles

Sounds good, at least I got double protections then

Putting zinc sheet under roof tiles. Hmm, thats got to be something new... to put it honestly, i am not a roofing expert as my experience more on insulation.

Usually a double metal roof system, its quite a good and guarantee that u ensure that u wont have leakages. Even if the top layer is rusted (max lifespan for quality one is about 25 years), you can alway change the top deck.

However for roof tiles is different due to the fact that they need to sit on purlin. ( google metal roof purlin). So how do u secure the zinc sheet?
So if you refer to Monier Malaysia system, u will notice that they only add the aluminium bubble foil to create a system either for reflection of UV or air circulation movement. If u look carefully on their architecture drawing, this foil do not touch the roof tiles, so it has a gap for air movement and to reflect UV.

If the contractor plan to install a metal zinc below the roof tiles ( let just say it legit, and the roof truss and frame can support it), then why install the aluminium foil sheet?

Having a sheet of metal itself already, u wont be able to identify the leakages.
But what i can say, if the contractor is able to do it... there is on thing guarantee... pencuri tak boleh masuk.

Even with roof tiles, you can do the double roof system.

Clay tiles are definitely cooler than the concrete tiles.

To reduce the heat in the roof attic, can install a good ventilation system.

End of the day is depend on your budget for your roof system.

mind sharing how much did it cost you for the following (how many sq ft):
1. clay roof tiles plus foil sheet and what brand?
2. zinc underlayment.

This post has been edited by IMF2025: May 19 2020, 01:58 PM

Not done yet, around 9k+ normal end lot but many slopes
roof tiles not included, just patch back or change on my own cost
i did not ask about brand of foil & zinc sheets, care to share what brand is good?

what does it cover for 9k? zinc and foil for whole roof ?

not a pro to recommend foil sheets but Monier and GCI have their foil sheet products. many different specs so depends on your budget.

Yes, to removed existing tiles put foil+zinc with some timber work for support then put back the roof tiles and patched all joints.

if roof slope gradient >30 , why the contractor want to put a 'paperlike' zinc ?

Most of the leakage caused by joint, valley or roof tiles material give way after years, and also the not so quality frame/ battern deflected.

peace of mind i guess. sooner or later his roof tiles will give way and leak?

are you a roofing expert pucca? or have experience in roofing works?

Can PM you & sent my roof snapshot for advice?

hi anyone got any good contacts for gutter specialist ? wanna do
low profile custom cutter.

or anyone who does aluminium works. thank you