Window to French Doors for Kitchen Extension

[tim00]

1. in your case i wouldnt bother with a cavity tray - simply run a srip of DPC along the head of the frame.
2. from the info. and pic given i would imagine that this original job ie. the kit. extn. was built without Blg. Regs i also assume that this frame is at the rear of the structure. Your joists are running the wrong way for cross-ventilation. Traditionally, if possible the ceiling joists would be run across the extn. to enable cross-ventilation - i see no sign of a ventilation gap in your pic, perhaps i'm wrong. what you seem to have is a cold roof with no ventilation. not much can now be done about it.
However, as regards the insulation then merely stuffing the joist bays with whatever depth of fibre-glass rolls they will take providing that a gap of 50mm is left above the insulation.
You could also go for polystyrene sheeting(ask at suppliers for further info) this would involve adjusting the electrical to finish surface.

 

[phykell]

Well, here's an update for anyone interested!

Eventually I managed to get the bricks out and fitted two 8ft concrete lintels cut to size. The overhang on each size easily exceeded the minimum required (150mm). In fact, the minimum was measured at 170mm! When I pulled out the inside course of bricks I had a prop bought from MachineMart for around £30. The following picture shows the opening with both inside and outside lintels fitted, and you can also see the old wooden lintel still in place:

http://www.phykell.co.uk/diy/LintelsFitted.jpg

The bricks were really difficult to remove due to the exceptionally strong mortar mix and the use of engineering bricks. My 850W rotary hammer started smoking and was replaced by a 1010W rotary from Focus which was good value at only £30! However, for cleaning up to get the best possible opening for the lintels at either end, I used an air chisel, which promptly broke its spring (no-one stocked a spare unfortunately) and I had to do the rest by hand!

Removing the window and knocking the rest of the wall down was easy:

http://www.phykell.co.uk/diy/KnockingWallDown.jpg

This left the opening ready to take the new doors:

http://www.phykell.co.uk/diy/OpeningReady.jpg

And here they are fitted (with DPC underneath of course - though the whole thing sits above the DPC anyway):

http://www.phykell.co.uk/diy/DoorsFitted.jpg

So now I just have to cement the lintels in place, and fill the gaps between the frame and walls.

to prop your ceiling joists up merely use a bottom plate the width of the opening, two props-at either end and a top plate.

Thanks for that, see the use of the prop above

- set a drip cap above your frame to throw off water... ... in your case i wouldnt bother with a cavity tray - simply run a srip of DPC along the head of the frame.

There's a fair-sized gap between the head of the doors and the lintels. It's been suggested that I use either a cavity tray or DPC but I'm not sure to be honest. I guess the DPC and a piece of wood would suffice but what is the DPC for anyway and what's a drip tray? Is it the cap I saw when I took out the window (a strip of profiled PVC).

The doors are quite firmly fixed but there is some flex at the very top. I guess this will disappear once I use mortar and foam to fix the lintels and fill in the gaps. One thing that concerns me is that if I use DPC along the top, what will be holding the top of the frame in or must I then use frame fixings along the top as well?

A friend of mine who had some windows fitted recently, by a well-known national company, said they didn't even bother using frame fixings, they just used the foam

One further question but this might not apply to many types of French doors, the middle hinge (which you can't really see in the picture) is a so-called "compression hinge". There's supposedly a part which you screw into the door frames once the doors are fitted but I really can't see how they fit at all. Has anyone seen these or even fitted them?

 

[masona]

The doors are quite firmly fixed but there is some flex at the very top. I guess this will disappear once I use mortar and foam to fix the lintels and fill in the gaps. One thing that concerns me is that if I use DPC along the top, what will be holding the top of the frame in or must I then use frame fixings along the top as well?

We only use frame fixing on side jamb and did you know you can get clip on extension bar top or side jamb that clipped onto your outside upvc frame ? They come in 5mm, 10mm, 15mm & 20mm thickness. I think you've gone a little too high with the lintel height but it's not a problem.

A friend of mine who had some windows fitted recently, by a well-known national company, said they didn't even bother using frame fixings, they just used the foam

They might have use fixings but you can't see it, if they haven't then there're cowboys.

One further question but this might not apply to many types of French doors, the middle hinge (which you can't really see in the picture) is a so-called "compression hinge". There's supposedly a part which you screw into the door frames once the doors are fitted but I really can't see how they fit at all. Has anyone seen these or even fitted them?

A picture may help us.

 

[phykell]

We only use frame fixing on side jamb and did you know you can get clip on extension bar top or side jamb that clipped onto your outside upvc frame ? They come in 5mm, 10mm, 15mm & 20mm thickness. I think you've gone a little too high with the lintel height but it's not a problem.

I used some white PVC drainpipe with a piece of 3x2 stuffed down it!

http://www.phykell.co.uk/diy/DoorsSecured.jpg

A picture may help us.

Sorry about the delay in replying. I've been working away. See what you think:

http://www.phykell.co.uk/diy/CompressionHinge1.jpg
http://www.phykell.co.uk/diy/CompressionHinge2.jpg
http://www.phykell.co.uk/diy/CompressionHinge3.jpg
http://www.phykell.co.uk/diy/CompressionHinge4.jpg

It looks fairly reasonable at first, but there is a significant gap and the metal plate is only screwed in. I just wonder if this is secure enough to hold the plate in place. I'm just hoping that perhaps it will ease after a while, and the rubber seal has compressed a bit... Has anyone seen a "hinge" like this before?

[edit] This is fixed now. A friend of mine who's a bit more practical than I am, fitted the hinges and they work just fine despite my concerns

This is now nothing to the latest problem I've discovered. It's the other window I have which is now the biggest worry, but perhaps I should start a new thread for that one..