Roof window

[Doug71]

I have been asked to make a small replacement roof window by a customer. The previous one was only single glazed, almost like a Dutch light on a greenhouse roof and just sits on a lining.

The new one will be double glazed with a unit that is stepped at the bottom.

I just wondered how people finish these at the bottom, would you still sit the unit in a rebate in the bottom rail to protect the edges of the unit with just the top pane hanging over?

Also how do I protect the spacer bar in the bottom of the unit from the sun, I have seen stick on lead tape used on some roofs like you would use for putting a diamond leading pattern on glass, is that the best way?

I know it is hard to picture but any advice appreciated.

Thanks in advance, Doug

 

[RobinBHM]

When I do roof lights fixed or opening, I use exitex capping system around the top and sides.

Either the flat glazing capex can be used or a gable bar which has a downstand.

http://www.questhardware.co.uk/glazing- ... ofile.html

I would make the sash just flat with no rebates, then plant on to form a rebate for the glass.

At the bottom, the step can overhang the end of the sash to form a drip. The underside of the glass should have a length of rafter gasket to stop draughts and driving rain.

Generally conservatory makers have used self adhesive flat lead to protect the spacer bar. We use a lot of stepped glass, but our supplier makes the units and does not attach any lead, however the mastic at the step is very wide, probably 20mm at least. They provide a guarantee, so I guess it must be OK. These days most conservatory glass has a self clean coat which makes sticking lead to it difficult.

 

[Jacob]

Unless there's a very good reason I'd just buy a Velux. They are really well designed, good value, easy to fit.

http://www.velux.co.uk/products/roof-windows

Top tip: splay the reveals, you get much more light, especially if it's a small one.

 

[skipdiver]

+1 for Exitex.

As Jacob says though, it's a much simpler task to fit a velux. If the customer will go for it of course.

 

[Doug71]

Thanks for the advice, looks like the exitex stuff is the way to go. Can't use a velux as opening/lining etc already there and don't want to start messing with all that.

Thanks again, Doug