whats the correct shingle tile overhang?

[mattu27]

Hello, I've got another thread about a playhouse that I'm building but thought this would be better in the roofing section.

After looking on the net I've seen various measurements from 10mm on all sides to 25mm on all sides.

Using the standard three tab felt shingles what's the correct overhang at the start and edges of the roof?

I know to reverse the first shingle and cut the tabs off but should I also have the same setup at the sides of the roof so that the edges are sat on a bitumen strip and don't lift in the wind.

It's mostly american videos and demos that I've seen but I'd assume that the same applies over here.

They also have shingle drip edge but I've not seen this anywhere that I've looked for a reasonable price.

Thanks, Matt

 

[catlad]

Its going to depend how you are going to detail your gutter I guess
its a soft material so if you go 50mm over which is normal for slate and
tiles generally its going to sag in summer, you put a strip of ali at the bottom
to lay your first course on if you wanted a bigger drip edge.

 

[mattu27]

Its going to depend how you are going to detail your gutter I guess
its a soft material so if you go 50mm over which is normal for slate and
tiles generally its going to sag in summer, you put a strip of ali at the bottom
to lay your first course on if you wanted a bigger drip edge.

Thanks for the reply, I was going to not have a gutter as I think it'll overpower the look of the playhouse even with mini guttering installed. Is a strip needed in that case?

 

[catlad]

No you don't need a strip if you are not going with a gutter just make sure it
overhangs enough to cover your deck.

 

[mattu27]

No you don't need a strip if you are not going with a gutter just make sure it
overhangs enough to cover your deck.

That's the issue, I'm thinking about 20 to 25mm but not sure if I should overhang the sides aswell.

Thanks

 

[catlad]

Can you not put a baton on the side to stop the water coming of the side
and then finish with a pvc trim?

 

[mattu27]

I see what your saying but it means the roof will be kicked up if I understand that right?
I've already made the fascias from PAR softwood and painted on all sides. What about if I fit the shingles with a some 25mm angle pvc trim underneath, is that what you meant? If it's siliconed in place then it should eradicate any capillary action.

Or I could retrofit it if I get problems later?

Shall I do 25mm front and 20mm on the sides then?

Thanks

 

[mattu27]

Update, so I've started the tiling today, and have gone with a 20mm overhang on all sides. If it looks daft I can always trim but the instructions on the net for theses shingles say to oversail by 50mm on the front! Which is madness.

Struggling now with the dormer windows, I've attached a photo mocking up how I aim to clad them after the tiling is done. Do I just tile upto the wall, seal the perimeter and then seal under the cladding whilst fitting it?

How do I finish the front? I've seen that the Americans use L shaped aluminium sheet and upstand it against the front, this is then wrapped round the side and up the roof.

The window isn't lined, framed or fitted so I've got some leeway.

Thanks.

 

[datarebal]

at the bottom start with a drip batten as you would on a flat roof. the same system can be used all round. (eaves and Verges)
You need to form an upstand to the side of the dormer and do not trust mastic alone.
This might help http://www.icopal.co.uk/Products/Pi..._Roof_Shingles/Roof_Shingle_Installation.aspx

 

[mattu27]

Thanks for the reply, after looking at the instructions and following your advice I've been and purchased some lead to do the flashings. Did think of flashband but seeing as I've already spend a fair chunk of money £30 on a roll didn't seem too bad.

Going to make the upstand as you say and form around the corners of the dormer. Then make some lead soakers for the angled section. Have no idea what I'm doing but wish me luck!

Watched some YouTube videos which might help or hinder, but we'll see.

 

[mattu27]

Continued tiling the roof and have made flashings out of some spare velux roofing trim that I had sat in the garage, I made soakers from this aswell which saved me using the lead.

Got upto the valley section but am unsure how to continue as I've seen three ways of doing it. Overlapping, open valley and closed valley. Anyone got any tips? Should I put a lead valley in? How do I cut the membrane so that it doesn't cause issues?