Replicating window cills in-situ

[jayc89]

I'll be casting 4x cills over the weekend, trying to replicate these;

 

 

The cills I'm tackling are the 4x upstairs ones (front 3 and 1 to the side). They're 1x brick tall and don't look to extend wider than the opening massively, perhaps by 50mm, or 2" back in the day? Similar the overhang isn't that much either, perhaps by the same measurement again?

 

From the cills we have left, they look to be Yorkstone so I'll be taking inspiration from a previous post, shuttering up the opening and using a mix of 1 white cement, 1/2 hydrated lime and 4 plastering sand. 

 

 

The windows going in are 128mm deep. I want them to sit half on the cill and half on the IWI that will be fitted behind the cill to reduce thermal bridging. 

 

Assuming the windows should sit back from the brick face by approx 50mm (I can't find any hard and fast rule for this), I'm thinking a cill depth of ~ 114mm makes sense (64mm of the window frame + 50mm back from the brick face + 50mm overhang).

 

Giving the final dimensions as; Length: (Opening width) + 100mm (50mm each side), Height: Brick height (4 1/2"), approx. 115mm) Depth: 115mm.

 

I was expecting the depth to be more. Can anyone spot any obvious floor in my plan?

[Gone West]

I cast replacement window sills at my old Victorian cottage in the nineties. I did much the same as you except I put lengths of rebar longways in the mould to strengthen the extended ends.

[Dave Jones]

you may want to add stools at either end to take the brickwork and an upstand to take a stub cill, like this

 

[jayc89]

1 minute ago, Dave Jones said:

you may want to add stools at either end to take the brickwork and an upstand to take a stub cill, like this

 

 

The original's don't look like they were stooled, the two originals we have left at the back of the house certainly aren't, they're just lengths of stone. I was planning on having a slight fall to the front and a drip groove built into the formwork though. 

[jayc89]

First window out and cill poured. Will sponge off and get the new window in tomorrow morning. The 80s uPVC frames are featherweight in comparison to the new ones!

[Dave Jones]

photos please.

[jayc89]

11 hours ago, Dave Jones said:

photos please.

 

I'll get one tomorrow. 2nd, of 3 windows, is out and cill poured so it will be a nice before, during, after shot. 

[jayc89]

Pretty chuffed with how it’s coming along. 

[jayc89]

Today’s turned into a bit of a shitshow.  Dry fitted the second window to find the spring in one of the sash runners has jumped off so we have a drifting sash. Looks like we need a special tool to pull it out of the housing and back onto the cam. 
 

Went to take out the third window and found a massive gap above the old wooden lintels, and the original sash window head still floating around up there. God knows how it hasn’t all come crumbling down yet, but I’ll be ordering some new lintels tomorrow…

 

Day off tomorrow, lintels hopefully here come Wednesday and hope to have the rest of them in by the weekend.

 

 

[jayc89]

3 hours ago, jayc89 said:

Today’s turned into a bit of a shitshow.  Dry fitted the second window to find the spring in one of the sash runners has jumped off so we have a drifting sash. Looks like we need a special tool to pull it out of the housing and back onto the cam. 
 

Went to take out the third window and found a massive gap above the old wooden lintels, and the original sash window head still floating around up there. God knows how it hasn’t all come crumbling down yet, but I’ll be ordering some new lintels tomorrow…

 

Day off tomorrow, lintels hopefully here come Wednesday and hope to have the rest of them in by the weekend.

 

 

 

Looks like this is what I'm going to have to do - 

 - given it's a brand new window, I really don't fancy cutting a bloody hole in it! I'll speak with the manufacturer to see if there's anything they can do. Pretty sure it's nothing that we did and it arrived loose... 

[jayc89]

Upstairs windows done.

 

 

Need to find a builder to change the openings for the downstairs ones to go into now. Seriously starting to consider doing that work myself too, finding a decent builder who has the understanding and appreciation to work on older properties seems a real struggle around my area.