Replacing window

[Matt615]

I am planning to replace the kitchen window in my 1930s house. It currently has an early eighties aluminium double glazed unit which is very draughty, so I want to replace with a new upvc one.

On pulling off some of the sealant round the edge, I can see the old window seems to be fitted it some kind of Woden frame inside the wall cavity. It kind of surprised me, as I was expecting the window to be screwed into the brickwork.

My questions is: Is it normal practice to just screw the new upvc window into this wooden frame, or is there going to be more to it than that?

Thanks

 

[Matt615]

Anyone?

The current window is screwed onto pieces of timber which are fixed inside the wall cavity. Is it ok to fit new upvc windows by fixing them to this piece of timber? Or is there another method which should be used these days?

thanks

 

[crank39]

Firstly aluminium frames are usually but not always fitted into a hardwood 'subframe', the subframe is fitted between the brickwork with the ali frame set into that, are you saying you have no subframe but the ali itself is fitted between the brickwork?

If this is the case and the fact you say the frame is screwed into pieces of timber (i assume hammered into the cavity) i would hazzard a guess the frame is set that far back that the fixing screws would end up in the cavity and not hold anything hence the timber 'chocks', you shouldn't really have anything bridging the cavity as it could cause damp to bleed or wick through, if thats was the only option i would wrap the timber chocks in DPC first but if possible i would push the new frame forward so the inner face of the window is flush with the inner face of the outer skin of brickwork, obviously this would involve a bit of making good internally with plaster