how to get a slope on a box gutter

[bazmdiy]

Hi all,

Can anybody please help me with a box gutter construction problem?

I have two roofs making a horizontal valley into which I am making a box gutter. The gutter is formed on an oak beam 5.2m long and the beam is "flat" (its actually 20mm higher at one end ie 1:255). I am trying to increase the slope to about 1:100. Creating finely tapered pieces of wood 5m long seems impractical. Is there some substance I can tamp down?

Many thanks for any suggestions

 

[catlad]

Go to your local timber suppliers and ask them to rip some timber in half to make a couple of tapers, then you can buy a piece of 6x1 or what ever will do to fix on top.

 

[bazmdiy]

Thanks catlad,

thats an idea I never had. I need to go from say 1.5" to 0.5" over 5.1m and I think they may be able to do it.

 

[cotswoldbuilders]

You can buy Firring strips already cut from most builders/roofers yard.

 

[joe-90]

Every box gutter I have ever seen stays flat with water in it. Why worry about it? No-one else does.

 

[cotswoldbuilders]

Every box gutter I have ever seen stays flat with water in it. Why worry about it? No-one else does.

It would be better if no water was holding, especially if its lead, ie contraction of the lead due to different temperatures causing splits, if the op is using lead, he might need to consider fitting some steps in the valley.

 

[joe-90]

Oh right, for some reason I was thinking conservatory/roof in PVC.

 

[bazmdiy]

I went throught the whole process of considering lead. It would have needed 2 drips giving three bays. Each bay would have needed some fall so total say 5". At one end of the valley we would have needed to go 500m up the rafters with lead and lose 2 rows of slates. Another suggestion was two expansion joints. It all got very complicated and in the end we were persuaded to go GRP. God I hope it doesn't leak!*? There is a previous post with a leaded valley with drips and they had problems with snow and ice build up.

Thanks for the furrings suggestion. I'm sure the local timber merchants will be able to help. I'm going there on Sat.

 

[Nige F]

and in the end we were persuaded to go GRP. God I hope it doesn't leak!*? .

The Reliant Motor Co. of Tamworth Staffs. used GRP - Great British Engineering

 

[bazmdiy]

my wife says she soes not want a Reliant Robin on the roof - plus a few other things I can't repeat...