Are all grp flat roof manufacturers the same?

[[email protected]]

Looking to diy replace my felt flat roof with grp fibreglass, the area is 5sqm

There are alot of brands out there cureit, cromar, restec etc all vary in terms of costs

I've found the following product on eBay at a reasonable cost

https://www.ebay.co.uk/itm/23349308...uid=zSqMOFlKQ9G&widget_ver=artemis&media=COPY

Are all the different products essentially the same? I.e materials/chemicals etc just different brands

Would you recommend the eBay product or does anyone have any other recommendations?

 

[freddiemercurystwin]

Like many, they're a trader who happen to have an ebay shop too. https://www.fslplymouth.co.uk/

 

[[email protected]]

Like many, they're a trader who happen to have an ebay shop too. https://www.fslplymouth.co.uk/

Have you used the product?

 

[oldbutnotdead]

There are different grades of resin, the stuff is date-sensitive to an extent (more for marine and aerospace use but still better using fresher).
Catalyst is hydrogen peroxide, a good vendor will ask you whether you want summer or winter grade.
Topcoat is resin with colour binder in it, catalyst is the same as for laminating resin.
Mat is mat.
I've used that brand of resin shown in the eBay pic, it works fine on rooves. 600g mat is a bit overkill unless it's a walkway.

 

[[email protected]]

The exact dimensions of the roof are 2550 x 1350mm

Was looking to purchase 1x 18mm OSB3 board 2440 x 1220

Given that the board shall be slightly short is it ok to use small off cut to make up the shortfall?

or should I buy a second board, cut as appropriate and place each board equally in the centre of the flat roof?

 

[oldbutnotdead]

You'll not see any offcuts from 1 board on that roof, if you've got big enough 18mm osb offcuts so you're not building a jigsaw it'll be ok (support all joins and bandage them when laminating). Better to use 2 full sheets but given current price don't blame you for trying to avoid it

 

[[email protected]]

I'm now thinking whether i should go for epdm instead, What would you recommend?

 

[Notch7]

I'm now thinking whether i should go for epdm instead, What would you recommend?

EPDM is less messy, less vulnerable to rain and for what you are doing will be done in one piece - bear in mind what you order may have a manufacturers join in it which is a bit thicker.

trims if you need them could cost as much as the rubber.

I’ve done EPDM a few times, it’s a great product - get a wide karnedean roller it’s worth it.

 

[[email protected]]

EPDM is less messy, less vulnerable to rain and for what you are doing will be done in one piece - bear in mind what you order may have a manufacturers join in it which is a bit thicker.

trims if you need them could cost as much as the rubber.

I’ve done EPDM a few times, it’s a great product - get a wide karnedean roller it’s worth it.

Decided to go with the EPDM option, planning on doing the roof on the weekend.

I'll be fitting 1x 18mm OSB3 board 2440 x 1220 straight edge but it'll be short by 5 cm on either side of the width and 3 cm either side length wise

A small expansion gap is acceptable but to make up the small difference could i fill the gaps with silicone sealant or expanding foam?

 

[^woody^]

The deck can't be smaller than the area it is intended to cover!

There should be no expansion gap as there is no expansion.

Small strips of board will bow between the joists unless supported.

 

[[email protected]]

The deck can't be smaller than the area it is intended to cover!

There should be no expansion gap as there is no expansion.

Small strips of board will bow between the joists unless supported.

I guess I'll have to purchase another osb3 board!

Couple of other questions
Screws or nails? What size?
What intervals should the osb3 board be fixed at?

 

[^woody^]

If you use ply, you can normally purchase half a sheet

 

[[email protected]]

If you use ply, you can normally purchase half a sheet

Should i use ply throughout instead? Or would it be ok to use a mix of osb3 and ply?

Which is better of the two?

Any ideas on the fixings?

 

[^woody^]

You could mix it and use a bit of ply for the strips, but I've always used ply as standard for any flat roof.

4.5 or 5mm galvanised screws min 60mm at 200mm or flat head galvanised 75mm at 150mm or 65mm ring-shank

 

[oldbutnotdead]

OSB3 is better for GRP (the resin soaks into the board), ply or a mixture is fine for EPDM.