What roof covering?

[hazzabo]

Evening all. I’m in the process of extending my shed at the bottom of the garden, and am having a bit of a quandary regarding what to cover the roof with. The existing covering on the original shed is torch on felt, and has been faultless for the last 10 years. It was fitted by my neighbour who is no longer available. I would also like something more visually appealing than felt. I will strip the existing roof and redo that at the same time as the new roof. Options are rubber, GRP or metal cladding. I will doing it myself with assistance from mates. Costs all seem to be about the same ballpark. The metal profile cladding appeals because It needs general practical skills to fix, whereas the grp and rubber are a step into the unknown for me, and I have heard horror story’s with grp curing too quickly or not at all, and the rubber ending up with bubbles and creases. Also, the current roof does not have any drip edges or anything- are they essential for the grp or rubber? The finished roof will be about 10m x4m. Interested to hear your thoughts and experiences. Many thanks.

 

[qwakers]

grp is easy, long lasting and easily repaired if damaged.

its my go to.

 

[gaz1]

all of these needs a osb board or plyboard except for the insulation type

cheapest option is tar and felt

which is melted felt sheets by heat gun also depends on how many coats you do single coat expect 3-5 years

i will stay out of that one as @roofman is the better one on that side of it with good guarantees

rubber not my sort of thing can be cheap or expensive but thats fixed by gluing to the surface so no hot melting on the roof

grp is expensive but will last 30+ years
this is also no hot works and is rolled on and laid on by a roll and rolled again before painting

metal roof also expensive theres 2 types

metal roof no insulation cheaper costs or with insulation and can be dearer

 

[addjunkie]

Metal with out insulation of some sort is prone to condensation. You can get it lined with anti con felt, but all thatdoes is reduce the drips.
Fibre cement is another option.
Theres onduline too, with out a osb deck its prone to sagging in the heat.

 

[slim_boy_fat]

I got Corrapol when the felt on the cave started to show its age. Easy install and cheaper than steel sheet.
I dealt with a company near Glasgow, excellent service
https://www.clearamber.com/browse/sc-CORRAPOL_BTBITUMENSHEETS-407/

Seems to be holding up well, but it you're in an exposed location, use the long screws as opposed to the nails to secure it.

 

[striker]

I have grp on my shed and pergola. It's fit and forget. I will do my log store this year and all three should see me out!

 

[8ob]

With the current price of ply etc I would have thought the pre insulated box profile sheets would start to look competitive. @roofman How much does a flat roof cost these days?

Bob

 

[More Amps]

Well just for balance, I'm a rubber roof fan. I did my first rubber roof last year and was pleasantly surprised at just how quick and easy it was - it was only a 12' x 8' apex shed, but I finished the main roof in an afternoon and finished off the edges the next morning. No bubbles in the rubber - I just rollered on a good coating of adhesive and then used a rubber roller to take out any creases. I could see if you were doing it on a hot day you would have to careful about the glue drying before you were ready to roll the sheet over but that would be my only minor concern. With a fifty year guarantee, I won't be the one putting in a claim!

 

[roofman]

With the current price of ply etc I would have thought the pre insulated box profile sheets would start to look competitive. @roofman How much does a flat roof cost these days?

Bob

For a 20 year life torch on system about £50 per m2 supplied and fitted on new build...£65-£80 on an existing old roof.

 

[roofman]

Well just for balance, I'm a rubber roof fan. I did my first rubber roof last year and was pleasantly surprised at just how quick and easy it was - it was only a 12' x 8' apex shed, but I finished the main roof in an afternoon and finished off the edges the next morning. No bubbles in the rubber - I just rollered on a good coating of adhesive and then used a rubber roller to take out any creases. I could see if you were doing it on a hot day you would have to careful about the glue drying before you were ready to roll the sheet over but that would be my only minor concern. With a fifty year guarantee, I won't be the one putting in a claim!

We are ripping rubber roofs off very frequently because the glues have failed.

 

[More Amps]

We are ripping rubber roofs off very frequently because the glues have failed.

Now you tell me! Though the adhesive that came from the rubber company was about £45 for five litres and looked a bit like PVA... I wouldnt be surprised if John Wayne and his chums were using PVA as a cheap substitute!

 

[roofman]

Now you tell me! Though the adhesive that came from the rubber company was about £45 for five litres and looked a bit like PVA... I wouldnt be surprised if John Wayne and his chums were using PVA as a cheap substitute!

water based

 

[8ob]

For a 20 year life torch on system about £50 per m2 supplied and fitted on new build...£65-£80 on an existing old roof.

By the time you have bought insulation and decking it starts to make the £33 per square meter insulated box profile look very cheap. It would probably outlast any of the roof coverings.

40mm PIR Insulated Roof Panel – Anthracite Grey Polyester | FM Approved (1m Cover Width)Anthracite / 3.100m

Buy 40mm Anthracite Grey PIR insulated roof panels – FM approved, fire-rated, & in stock. Fast UK delivery, trade discounts, expert help available.

www.colourcladprofiles.com

Bob

 

[gaz1]

30+ years as long as youve done recommended applications

but bolt holes arnt coated so reduces lifespan same when you cut them so take into account they can fail earlier

 

[hazzabo]

Food for thought, thanks all. For the GRP, does it all have to done in one go? Can you do the drip edges one day, go back and do 1 half of the roof covering the next etc then topcoat all together?

I’m quite happy to have a go at either options, but knowing I could break it down into stages would ease the pressure.

 

[Porkypine]

I've favoured the old traditional galv "wiggy tin" for similar stuff I've done in the past, it's easy to deal with, doesn't make nasty dust when you trim it, and likely outlasts the other alternatives....

 

[owas]

I went for the easiest option, certainly doesn't look brilliant but for £265 plus some screws and sealant,was a bargain I thought.
I think I might paint it black to make it look better.. (edges are all cut now)

I'd have needed 11 plywood sheets to cover, so about 385 just for that

 

[bricol]

By the time you have bought insulation and decking it starts to make the £33 per square meter insulated box profile look very cheap. It would probably outlast any of the roof coverings.

40mm PIR Insulated Roof Panel – Anthracite Grey Polyester | FM Approved (1m Cover Width)Anthracite / 3.100m

Buy 40mm Anthracite Grey PIR insulated roof panels – FM approved, fire-rated, & in stock. Fast UK delivery, trade discounts, expert help available.

www.colourcladprofiles.com

Bob

Especially if you buy from one of the seconds places - think my double garage roof is better insulated than the house at 100mm thick! Damaged sheets top and bottom of the pallet - rest were perfect. I was able to use the damaged ones too, by simply cutting the damaged side off.

 

[gaz1]

Food for thought, thanks all. For the GRP, does it all have to done in one go? Can you do the drip edges one day, go back and do 1 half of the roof covering the next etc then topcoat all together?

I’m quite happy to have a go at either options, but knowing I could break it down into stages would ease the pressure.

grp dosnt take long after the boards are down as you do it by sheets of rolled matting and mixed glue

painted day after or days after has to be a dry day dont atempt if any rain is around

 

[gaz1]

there is also liquid rubber cant tell you anything about it but have seen it used