flat roof info

[DARTHVADER]

Hello All,

I'm just looking for some advice/costs.

My flat roof on my ground floor bathroom is shot. The chipboard at the front near the gutter had turned to pulp (some of the felt was actually installed too long and and was draped in the gutter soaking water)

It looks like the original old felt has been left in place and then polystyrene sheet has been 'tarred' into place on top followed by new felt on top of this.

This looks like it has had the effect of acting like a big 'capillary action sandwich' which has left damp spots and left the front as pulp.

I'm planning to possibly replace the deck myself with new ply or sterling board and my question is can a single skin felt type product be placed on top of this? (cold lay?)

The roof is small - approx 2.0m x 2.3m, so just shy of 5m2. What would (roughly) a builder charge for this...ball park to do the lot, including the insulation. The ceiling internally is exposed as I'm refurbing the room and the joists look sound, as does the majority of the chipboard in fairness aside from the front near the gutter.

Many thanks,

 

[Deluks]

Chipboard or sterling board? (often the 2 gets confused)
You could do it yourself, but how confident are you, Doesn't sound like a particularly difficult job to me. You'll want all the decking out if it's chip, and replaced with 18mm wbp ply. As for single layer you could get EPDM. Search here/Google/eBay for EPDM

With the insulation being on top you have a 'warm roof' is the insulation white (polystyrene) or yellow (proper stuff)

Info here.

 

[DARTHVADER]

Thanks for taking the trouble to reply Deluks.

I'm a fairly compentent at diy and feel the job is not beyond me. The complete chipboard strip out was something I thought I may have to do. Does 18mm wbp ply come as 8" x 4" ?

The EPDM looks like a real time saver.

The insulation goes on top of the new deck or below? the existing stuff is very thin rockwool type on the inside, with polystrene sheet to the top.

Cheers,

 

[masona]

Does 18mm wbp ply come as 8" x 4" ?

Yes but make sure the plywood edge is on the centre of the joist or put in an extra joist. Is it not possible to put a low pitch roof instead?

On the flat roof you will need to use battens across the joists on top of the firring strips for cross air-flow ventilation.

 

[roshboy]

If i were you i would consider getting a quote for a Fibreglass resin roof.

You could strip the old deck, use the 18mm wbp plywood and insulate yourself. Then get a company into do the fibreglass covering.

In this part of the world you are looking at around £60 m2 for the full service - stripping and new boards as well as the FRP coat. Dont know how much a company would charge for just the FRP coat - it is not cheap stuff to buy!

 

[DARTHVADER]

Thanks again for the replies...food for thought me thinks.