Patio over GRP roof

[rideforever]

Hi. If a 1st floor patio is done over a fibreglass roof, and it has decking ... does the deck just rest on the fibreglass and bolted to ... in this case it would be a patio 6x3m and the deck could be bolted to 2 walls in an "L" shape ... is that sufficient, or does it need to be bolted through the fibreglass roof or something? Doesn't the deck resting on the fibreglass damage the roof?

And to what is the balustrade attached ? if it's a short balustrade it could be bolted to end walls, but this patio seems a bit big for that, is it sufficient to bolt the balustrade to the deck and side walls ? Is there any way to attach the posts of the balustrade to the wall below on the outside - but what about the guttering?

Thanks for any help.

 

[oldbutnotdead]

Pictures. Or plans at least would help. Depends how good the deck is and how well the laminate went down. Gravity only wouldn't be wise (you'll get noise as well as eventual damage from expansion/contraction), fixing through would be best but fix thru to joists not just the deck- long screws would do.

 

[rideforever]

..

Only got photo right now, there's a tiled roof with attic space. I'm thinking to strip it down put a grp roof on and turn it into a patio. I am thinking about how to fix the decking balustrade so it's solid.
If piers go through the roof to connect with the structure below, how to waterproof them?
I passed by some balconies on the weekend that had the balustrade bolted to the wall below on the outside but don't know how the guttering works then?

Perhaps it would be better to use brick to build up the walls and use a waterproof cement floor with tiles, drainage through holes in the walls ?

Just trying to find something practical and as simple as possible.

 

[oldbutnotdead]

Well that's not a flat roof for starters. You'd need vertical upstands through the roof to support your deck, flash them like you'd flash a chimney.
And before you go any further you do realise that the odds of you getting planning permission for this structure are somewhere between slim and none?

 

[rideforever]

..

Planning is no problem there are a few of these in adjacent properties.
What would you recommend for the easiest way to convert it into a balcony?
Cheers

 

[freddiemercurystwin]

Pictures. Or plans at least would help. Depends how good the deck is and how well the laminate went down. Gravity only wouldn't be wise (you'll get noise as well as eventual damage from expansion/contraction), fixing through would be best but fix thru to joists not just the deck- long screws would do.

Fixing through should be avoided at all costs and is completely unnecessary, a timber or paved deck will sit there quite happily under it's own weight, the OP needs to utilise something some like support pads eg https://www.google.co.uk/search?q=wallbarn+paving+supports&sxsrf=APq-WBuP_vIM1y3tLVk_4wbZrIHS_yogLw:1648065754366&source=hp&ei=2nw7Ypi_FOSBhbIP-uizqAo&iflsig=AHkkrS4AAAAAYjuK6vDI8uwKB67ueoTVwzmWOgSKHvUa&oq=walburn+paving+suppo&gs_lp=Egdnd3Mtd2l6uAEB-AEBKgIIATIGEAAYFhgeMgYQABgWGB4yBhAAGBYYHsICBBAjGCfCAgUQABiRAsICBBAAGEPCAgsQLhiABBixAxiDAcICCxAAGIAEGLEDGIMBwgIOEC4YgAQYsQMYxwEYowLCAhAQLhixAxiDARjHARijAhhDwgIHEAAYsQMYQ8ICChAuGMcBGK8BGEPCAgoQLhjHARijAhhDwgIHEAAYyQMYQ8ICChAuGMcBGNEDGEPCAggQABiABBixA8ICEBAuGIAEGIcCGMcBGK8BGBTCAggQLhiABBixA8ICCxAuGIAEGMcBGK8BwgIOEC4YgAQYsQMYxwEYrwHCAgUQABiABMICBRAuGIAEwgIOEC4YgAQYxwEYrwEY1ALCAggQLhiABBjUAsICCxAuGIAEGNQCGMkDwgIHEC4YgAQYCsICCBAAGBYYChgewgIFECEYoAFIg0tQAFihPnAAeADIAQCQAQCYAbkBoAHiDaoBBDE2LjQ&sclient=gws-wiz Commercial patio's/decks on top of flat roofs are never fitted down. The OP also needs to bear in mind his proposals will need planning permission and Building Regs approval both of which can be very difficult and costly as a retrofit to achieve. He's already stumbling across a few of the multitude of complex things to overcome when undertaking such a project. Unless he's doing it on the QT of course or doesn't mind of someone falls off one day.

 

[freddiemercurystwin]

There are a few other threads on the forum if you search eg https://www.diynot.com/diy/threads/how-to-fix-decking-to-fibreglass-flat-roof.237647/#post-1712621

 

[catlad]

If you have two wall to fix to then that is plenty.

 

[rideforever]

Thanks for the answers ... and the balustrade can be fitted as part of a deck without further support as well?
Another question is, is there a better surface than GRP that is fireproof, for BBQs etc..? Is there a flexible concrete with membrane or something like that?
Cheers

 

[rideforever]

..

 

[rideforever]

OSB doesn't look strong enough to take a deck resting on it.
What about doing half thickness ply, half thickness OSB ?

 

[noseall]

. and the balustrade can be fitted as part of a deck without further support as well?
Cheers

No. The balustrade and handrail will need to be a specific minimum height and design to prevent small child fall through etc. It will need to be structurally fixed and proven.