Interior cills

[vfrdave]

So traditional build how do I close the cavity at bottom of windows and build up the cill level? How high does it normally come up, bottom of window and then window board?

 

Not the best images in the world but will give you an idea of what I am talking about.

 

 

[Declan52]

The top pic needs another course of block on it's flat. 

You need to figure out what you are using for the internal cills, 18mm MDF or 25mm oak or ???

When you know what it is then you can mark on the frame where you can it to come up to. Then measure down and see what you have left. I had near 80mm so I cut a piece of 50mm insulation board and put it in so it closed the cavity. The front edge is left back 50mm and then you put a piece of level timber across the opening set at the height you need it to be for you board to sit on. Don't forget to add 15mm for whatever adhesive you plan to use, expanding foam is what I used. Then mix some concrete and fill the hole. And smooth it level.  Once it's went off then you can put the cills in and stick them down.

The insulation is basically to reduce the cold bridge you will have from the concrete cill. 

[vfrdave]

4 minutes ago, Declan52 said:

You need to figure out what you are using for the internal cills, 18mm MDF or 25mm oak or

I will raise the issue again with the missus, lost count how many times I have tried to get her to look at this.

5 minutes ago, Declan52 said:

insulation board

Do you mean pir?

[vfrdave]

7 minutes ago, Declan52 said:

15mm for whatever adhesive you plan to use

Is that not alot of adhesive?

[vfrdave]

Sorry @Declan52 not sure I'm reading this right do I fill the front to the level the window board will sit on and leave the insulation board lower to allow for depth of adhesive and window board.

[Declan52]

Yes pir.

15mm gives you a bit of play incase you haven't levelled it spot on.

Excuse the drawing, am half cut watching the Liverpool match!!

The red is the insulation.

The green is concrete.

The blue the cill board.

[vfrdave]

Thanks @Declan52

Shatter the nerves that last 10mins but a good win nonetheless #YNWA

[vfrdave]

@Declan52 I have one more question on this, concrete or sand and cement to fill?

[Declan52]

Will probably depend on how deep it needs to be. Concrete will be better though. You don't have to order a 1m3 in just mix it up in a barrow or the mixer if it's on site. 

It was getting enough timber to make the front edge was my problem.