Workshop Roof

[Geoff_S]

I am going to demolish my 30 year old workshop and build another in it's place. The old one has served me well, but is an extended shop bought shed, all built in 2"x 2" and is sagging/rotting/leaking and generally showing signs of collapse. I guess I could get a few more years out of it but it would only be delaying the inevitable!

So a proper bespoke job is going to be done this time with no compromise. 4"x2" frames. 6"x2" floor and roof joists, Celotex insulated, OSB boarded inside ceiling & floor, plasterboard and plastered, log lap on the outside. Plywood boarded flat roof.

Dimensions are 6.5x4.5 metres.

Now, this is not the cheapest thing to do, but I got a price for the felting of the roof. It's been suggested that it should be 3 layer felt, heat gunned on. I'm not averse to this as the workshop is right next to woodland and overhanging trees which have dumped loads of sap and general detritus on the roof. Experience suggests it has to be tough.

But, now to the cost ... £4,500 +VAT. That seems an awful lot for 3 layers of heat gunned felt to me.

Am I wrong?

Cheers

Geoff

 

[Fitzroy]

Can’t comment on the felt price as I’ve no experience in that area. I would however advocate for EPDM, it’s easy to fit and low price, my shed is under trees and after 6 yrs it’s still looking as good as ever.

There are different thicknesses of epdm, I went for the thinner stuff which is still very robust, but you could go thicker if you wanted.

A rubber roof kit for your sized building is about £800 inc VAT. It would take some one experienced about a day to fit with two people, say another £800 depending on your region. So I’d estimate 1500-2000 inc vat for someone to supply and fit.

Fitz.

 

[eribaMotters]

How about GRP?

Colin

 

[niall Y]

I am going to demolish my 30 year old workshop and build another in it's place. The old one has served me well, but is an extended shop bought shed, all built in 2"x 2" and is sagging/rotting/leaking and generally showing signs of collapse. I guess I could get a few more years out of it but it would only be delaying the inevitable!

So a proper bespoke job is going to be done this time with no compromise. 4"x2" frames. 6"x2" floor and roof joists, Celotex insulated, OSB boarded inside ceiling & floor, plasterboard and plastered, log lap on the outside. Plywood boarded flat roof.

Dimensions are 6.5x4.5 metres.

Now, this is not the cheapest thing to do, but I got a price for the felting of the roof. It's been suggested that it should be 3 layer felt, heat gunned on. I'm not averse to this as the workshop is right next to woodland and overhanging trees which have dumped loads of sap and general detritus on the roof. Experience suggests it has to be tough.

But, now to the cost ... £4,500 +VAT. That seems an awful lot for 3 layers of heat gunned felt to me.

Am I wrong?

Cheers

Geoff

For me , having little experience of felt roofs, it does sound a lot. But surely by giving the roof a slightly more pronounced slope, an alternative, like corrugated iron, would be cheaper; easier to install, and easier to maintain ?

 

[Spectric]

Why not use corrugated sheeting, comes in galvanised steel in many colors https://www.roofingmegastore.co.uk/roofing-categories/corrugated-sheets/metal.html or bitumen in various colors. Board the roof with PIR board sandwiched between sheets of stirling board and the use the corugated as just the waterproof decorative finish. You could paint the shhets to give added protection and I think corugated would look nicer than felt.

The other option is shingles, Roof Shingles | Roofing Shingles | Roofing Megastore

but as a woodworker you could use wooden shingles Roof Shingles & Shakes | Wooden Roof Shingles | Silva Timber

In both those previous cases I would still use the PIR sandwich first.

 

[Jameshow]

I would use steel sheeting. Much more durable than felt.

Put your insulation between rafter and osb to underside and your good to go.

 

[Doug B]

For that money you could do yourself a tiled roof

 

[Geoff_S]

For that money you could do yourself a tiled roof

Good point, I won’t but good point. Puts it in perspective!

 

[Lons]

As an ex builder I know I'm now out of touch but I'd have no hesitation in saying that price is a rip off, certainly not an amount I would pay, perhaps you should get other quotes to compare but my advice is to go for EPDM rubber as already suggested, it's easier to fit than felt and lasts a great deal longer, 30 years is not too much to expect.

 

[mikej460]

I wouldn't use felt and certainly not for that sort of cost, as it does perish over time. You could do it a lot cheaper using steel or onduline roofing sheets laid over a battened, breathable membrane. I used cedar shingles on our loose boxes and they look great but they are expensive and tricky to fit (unless you have experience of installing a slate roof), so you may need to pay a roofer to do it for you.

 

[Molynoox]

I am going to demolish my 30 year old workshop and build another in it's place. The old one has served me well, but is an extended shop bought shed, all built in 2"x 2" and is sagging/rotting/leaking and generally showing signs of collapse. I guess I could get a few more years out of it but it would only be delaying the inevitable!

So a proper bespoke job is going to be done this time with no compromise. 4"x2" frames. 6"x2" floor and roof joists, Celotex insulated, OSB boarded inside ceiling & floor, plasterboard and plastered, log lap on the outside. Plywood boarded flat roof.

Dimensions are 6.5x4.5 metres.

Now, this is not the cheapest thing to do, but I got a price for the felting of the roof. It's been suggested that it should be 3 layer felt, heat gunned on. I'm not averse to this as the workshop is right next to woodland and overhanging trees which have dumped loads of sap and general detritus on the roof. Experience suggests it has to be tough.

But, now to the cost ... £4,500 +VAT. That seems an awful lot for 3 layers of heat gunned felt to me.

Am I wrong?

Cheers

Geoff

Seems ludicrously high.
I'm no felt expert but for that money I would expect tiles or something, not felt!
As many have already advised, there are much cheaper options that will probably outlive you, EPDM being the most obvious.

 

[Lons]

Hear is the company we used for both my brother and nephew single garage roofs, that was about 4 years ago. They have installation videos etc so worth a look if interested in EPDM and loads of other installation advice on youtube. In my brothers case there was enough left over for a small shed and he didn't bother with off the shelf edging, just timber facia which have been fine.

https://www.rubber4roofs.co.uk/classicbond-one-piece-epdm-rubber-roof-covering-1-20mm

 

[Flynnwood]

But, now to the cost ... £4,500 +VAT. That seems an awful lot for 3 layers of heat gunned felt to me.

Am I wrong?

Cheers

Geoff

I would suggest they might not want or need the job - but have priced it at a point (where if you agree), they are onto a big win.

Do you know when they are booked up to? That might provide another clue.

 

[Scruples]

I am going to demolish my 30 year old workshop and build another in it's place. The old one has served me well, but is an extended shop bought shed, all built in 2"x 2" and is sagging/rotting/leaking and generally showing signs of collapse. I guess I could get a few more years out of it but it would only be delaying the inevitable!

So a proper bespoke job is going to be done this time with no compromise. 4"x2" frames. 6"x2" floor and roof joists, Celotex insulated, OSB boarded inside ceiling & floor, plasterboard and plastered, log lap on the outside. Plywood boarded flat roof.

Dimensions are 6.5x4.5 metres.

Now, this is not the cheapest thing to do, but I got a price for the felting of the roof. It's been suggested that it should be 3 layer felt, heat gunned on. I'm not averse to this as the workshop is right next to woodland and overhanging trees which have dumped loads of sap and general detritus on the roof. Experience suggests it has to be tough.

But, now to the cost ... £4,500 +VAT. That seems an awful lot for 3 layers of heat gunned felt to me.

Am I wrong?

Cheers

Geoff

I designed a timber shed back in 2013 when I retired. It was 5.5m long x 2.4m wide (a single garage size) with timber frame and plastic cladding.
The pitched roof was sterling board covered with one layer of felt and then felt roof shingles. The whole project cost me £8,000 including a base, floor, insulated walls and roof and the hire of a chippie for 10 days. I've had had no problems with the roof. However, the Wickes double doors in oak veneer have started to rot despite many coats of varnish.

 

[charles79130]

I am going to demolish my 30 year old workshop and build another in it's place. The old one has served me well, but is an extended shop bought shed, all built in 2"x 2" and is sagging/rotting/leaking and generally showing signs of collapse. I guess I could get a few more years out of it but it would only be delaying the inevitable!

So a proper bespoke job is going to be done this time with no compromise. 4"x2" frames. 6"x2" floor and roof joists, Celotex insulated, OSB boarded inside ceiling & floor, plasterboard and plastered, log lap on the outside. Plywood boarded flat roof.

Dimensions are 6.5x4.5 metres.

Now, this is not the cheapest thing to do, but I got a price for the felting of the roof. It's been suggested that it should be 3 layer felt, heat gunned on. I'm not averse to this as the workshop is right next to woodland and overhanging trees which have dumped loads of sap and general detritus on the roof. Experience suggests it has to be tough.

But, now to the cost ... £4,500 +VAT. That seems an awful lot for 3 layers of heat gunned felt to me.

Am I wrong?

Cheers

Geoff

I used the more modern material (Rubber for roofs)guaranteed for 25 years made by Firestone available on Ebay
easy to use just fool on the adhesive and stick it down they are very helpful for advice

 

[Jones]

With hot work being frowned upon by HSE these days I wasn't aware you could still get melt down felt, I haven't used it for 30 years. Grp or epdm are the modern better choices and you will find many more builders who are familiar with them and cheaper as well. As others have said insulated box section steel has lots of advantages if you're happy with a different look.

 

[Jameshow]

With hot work being frowned upon by HSE these days I wasn't aware you could still get melt down felt, I haven't used it for 30 years. Grp or epdm are the modern better choices and you will find many more builders who are familiar with them and cheaper as well. As others have said insulated box section steel has lots of advantages if you're happy with a different look.

With insulated steel sheets I doubt you would need joists tbh.

Just long screws into the wall plates.

 

[Phil Pascoe]

An acquaintance who works for a builder's merchant (very quickly) made a comment when I said I was considering metal/clear sheeting for mine - you won't live with the noise when it rains heavily.
Mine's going to be EPDM. I've increased the window area to compensate for not having light through the roof.

 

[Molynoox]

An acquaintance who works for a builder's merchant (very quickly) made a comment when I said I was considering metal/clear sheeting for mine - you won't live with the noise when it rains heavily.
Mine's going to be EPDM. I've increased the window area to compensate for not having light through the roof.

I wonder how noisy the kinspan metal sheets are? I'm talking about the ones with 100mm PIR in the middle

 

[Phil Pascoe]

Probably fine with the PIR.