How far in should a window be positioned

[dangti6]

Is there a ‘standard’ for the depth within the opening a window should be positioned?

 

Here I have placed the window about 25mm in which looks fine. I am going to have the exterior rendered, which would add say 10mm or so? Therefore to retain that depth once rendered I should fix it about 15mm inside by my estimations. Does that sound about right?

 

Also on a similar subject, I see people usually cut the sill to the width of the window when not having it overhanging each end. Is there any benefit to me cutting the sill straight, but a few mm wider than the window to make it neater when the render overlaps? (Opening is several mm wider either side to allow for expansion/packing etc).

 

 

[nod]

50 mil is an ideal minimum for render 

 

[Mr Punter]

If that is a cavity wall I favour locating the window a fair way back (80mm?) so that it is mostly in line with the insulation.  I cannot see cavity closers in your picture so not sure what cavity width you have?

[nod]

Looks like blocks laid flat 

Could be wrong. 

[dangti6]

It’s not a cavity wall, 215mm block on belly garage wall.

 

I imagine the benefit of setting it back in further is more surface area for render.

[nod]

3 minutes ago, dangti6 said:

It’s not a cavity wall, 215mm block on belly garage wall.

 

I imagine the benefit of setting it back in further is more surface area for render.

I set all ours at 50 and did the render myself 

[dangti6]

Very smart. Is that K rend?

 

I may well take the plunge and have a go myself. I wonder whether something like a roughcast finish may be better for a DIY effort. 

[nod]

1 hour ago, dangti6 said:

Very smart. Is that K rend?

 

I may well take the plunge and have a go myself. I wonder whether something like a roughcast finish may be better for a DIY effort. 

Rough cast is definitely more forgiving 4-1-1 mix 

[tonyshouse]

I like inside the masonry, fully in the insulation layer, fixed behind the masonry rain screen 

[joe90]

1 hour ago, tonyshouse said:

I like inside the masonry, fully in the insulation layer, fixed behind the masonry rain screen 

Ditto, I fixed my windows behind the brickwork, in the insulation zone and inner blockwork skin has a bigger hole so windows inserted from inside called check reveals  (and I angled my reveals ?).