Felt roofing technique

[The Bear]

Hi all

Currently building a new shed and want it to look good quality.

It is going to have fairly shallow pitch (probably 22.5 degrees), ridge down the middle so falls away on 2 sides.

Having looked around the neighborhood I see on some sheds that a far more professional job has been done with regards to the felting. No nails showing, edges at the eves and gables folded back under themselves so no cut edges showing, no crappy folds obvious. I am quite happy with the methods for sticking the felt down but need help with doing the edging to make it look good.

Anyone able to help or point me to where I can read up on this?

Thanks

Mark

 

[chippy1970]

I used the sticky back felt from Wickes guaranteed for 20 years I think and it rolled over the edges very well no cracks or splits. Its a bit pricey but well worth it if you don't have the gear to do a hot roof.

 

[Shultzy]

Mark, is the felting of the roof I have created in my workshop build what you are looking for. If so its the same as chippy1970 suggested, the sticky stuff from Wickes. The corners are glued down with "Easy Seal Lap Mastic ". The best way to practice is make a cardboard model of the roof and wrap it with paper so you can see how the corners fit.

 

[The Bear]

Shultzy,

The ones I have seen seem to have had the edges done separately to the main top area. They have a small piece of felt carefully folded up and overlapped to the top, with a separate large sheet(s) on the main flat surface. It really does look professional as all the cut edges are hidden where they are folded under themselves.
I'll see if I can get a photo. I have spoken to the owner of the roof I've seen but unfortunately the previous occupants fitted it.

Mark

 

[9fingers]

The technique uses strips of mineral felt about 300mm wide and cut off the roll so about 3' or 1m long.
Ideally do this when the weather is warm to keep it flexible.
Nail it on to the edge of the roof, mineral side to the wood and hanging down towards the ground. Carry on around the corners with 75 to 125 mm round each corner.
For the best edge, cut 75 x 10 mm timber strip and run a bull nose edge
on both long edges. Put adhesive on the felt from the top down 75mm.
Nail on the wood all round level with the top of the decking. Do a trial fold of the felt over the battens and see where you need to cut it at the corners to give neat corners.
Coat the remainder of the backside of the felt with adhesive and fold over the battens on onto the first 150mm or so of the roof deck. Fit a row of nails 25mm from the edge of the felt.
Run full width strips of felt from one side of the roof over the ridge and down the other side to overlap the row of nails.
Normally this would be done with torch on felt but using a good quality of bituminous adhesive should work as well.

hth

Bob

 

[The Bear]

9fingers/bob

From your explanation, I can see you know exactly what I am describing. Yes I am intending to do it with the cold bitumin system.

Am I right in thinking then that after nailing it felt side into the edge, then bend it up to bring it felt side out and create the overhang, I need to nail a batten inside the fold to create a nice continuous straight edge?

Thanks for the advice so far

Mark

 

[9fingers]

Hi Mark,

You don't need the batten but I think it will help make the folded edge neat and avoid the problems even the pros get where the felt cracks when folded back on itself.

The modern way of doing flat roofing uses a felt with the bitumen already on it covered by a very think plastic film. Flashing a gas torch over it melts the bitumen easily and does away with the cauldron of tar.
You might want to consider using this felt. Proper Builders merchants should stock this (not B&Q)

Bob

 

[The Bear]

thanks bob

 

[Mooeee]

Why don't you use the felt shingles from wicks or B&Q. They are like the roofing that they use in the USA.

B&Q do 2Sm for about £16

 

[Oldman]

I did this pent roof around 3yrs ago using the method Bob suggested. I didnt enclose a batton and if you look carefully you can see that where the strips overlap the next it gains a little kink due to one end having further to go than the rest of the strip. I used plenty of felt adhesive so its all well sealed but had to take great care with the folds to not split/crack the very heavy duty felt I was using.
Being the highest edge these strips went over the main felted area of the roof and were stuck down.

Still looks good today.

 

[The Bear]

Hi "Oldman"
That looks good
What brand did you use for the felt and adhesive and where did you get it from if you don't mind me asking?

Mark

 

[Oldman]

The felt was just roofers top weight stuff and the adhesive make I also cant be sure of now, buy from a builders merchant rather than Homebase etc would be a good bet, the normal shed weight felt isnt really worth bothering with imo as it just wont last.

 

[gidon]

Have you thought of felt shingles? I think they look far better than any alternatives for shed roofs. I was in Canada recently and nearly all the houses I saw were finished with them!

Very easy to lay - not sure how they compare in price to the sticky felt stuff.

My WIP shed with felt shingles:

Cheers

Gidon

 

[Oldman]

That roof looks really very nice Gidon, almost like slate.

What was the cost and how easy was it to fit?

 

[gidon]

Thanks Oldman. They cost £140 - plus you need an underlay (I used garage underfelt from B&Q). I finished a playshed with it too - the red shingles and they look nice too.
Cheers
Gidon