Box gutter

[S Godfrey]

Good morning everyone. This is my first post on this forum. I am currently in the process of planning an extension to my property. While I will be employing the services of professionals with some aspects of the job I am trying to do as much work as I can myself to try to keep costs under control.

 

We live in a 1950’s semi detached bungalow. Across one half of the rear of the property is a large hipped roof extension which forms the living room. We want to extend the adjacent kitchen across the other half of the property but the new build will extend only up to approximately 2/3 the length of the existing extension. We want to build a gable end on the new extension so we can vault the ceiling. The problem is what do we do about the guttering between the two hips? As the new build will not extend the full length of the existing extension we will need to install a right angle on the valley/box gutter to enable the water to drain into the existing gutter on the older extension. I had thought about fabricating a valley gutter out of fibreglass. Would this be the best solution? Thank you

[joe90]

Good morning and welcome. I am a fan of GRP and it would be my method of choice, as said many times before here it has to be very dry to do the GRP work, not sure if you have done any before?. If not there are many u tube vids to show you how. I have done a fair bit of GRP  flat roofs, box gutters etc .

[S Godfrey]

Thank you Joe

[nod]

1 hour ago, joe90 said:

Good morning and welcome. I am a fan of GRP and it would be my method of choice, as said many times before here it has to be very dry to do the GRP work, not sure if you have done any before?. If not there are many u tube vids to show you how. I have done a fair bit of GRP  flat roofs, box gutters etc .

GRP is Bomb proof 

[PeterW]

I would build a new gutter in OSB, line with 25mm PIR then another layer of OSB, and then GRP. Lap it up under the tiles until at least the first tile batten 

[S Godfrey]

Thanks Nod. Peter W - sorry if my questions seem a bit daft but what is PIR? Also would three layers mean the gutter would protrude too high to fit under the tiles? What sort of thickness OSB would be most suitable? Thank you

[PeterW]

PIR is insulation - Kingspan / Celotex branded if you’re searching for it. 
 

12mm OSB will be fine if well supported and only the inner layer goes under the tiles then covered with GRP so this is fine as it will be less than 25mm thick (tile batten thickness) 

 

 

[S Godfrey]

Thanks Peter

[joe90]

1 hour ago, PeterW said:

I would build a new gutter in OSB, line with 25mm PIR then another layer of OSB, and then GRP. Lap it up under the tiles until at least the first tile batten 

I have never heard of box gutters lined with PIR, why??

[PeterW]

14 minutes ago, joe90 said:

I have never heard of box gutters lined with PIR, why??

so this is bridging between two internal spaces - of you line them with PIR and they fill with ice or snow they don’t create cold points and potential condensation issues internally. It doesn’t cost much but can make it much better than just a flat timber gutter that can be a nightmare to insulate from the inside due to rafter ends etc. 

[Kevin J]

A box gutter Fabricated in Roofinox Tin Matt Grade 316 Stainless steel could be a simple investment 

at 0.5mm thick its lightweight so easily handled on site, no underside corrosion issue, boxed ends can be folded, origami style with outlet and internal corners soldered to design or in situ.

Properly Done once it's then forgotten with the exception of leaf cleaning every spring

www.roofing-tools.com supply soldering equipment and or fabrication services

[Alexphd1]

@Kevin J exactly our plan, still to be done....