Missing Window sills- should we replace them?

[finn]

Hi,

We're about to open up two old windows that have been blocked up for well over a century. The thing is, they don't have any sills- presumably they were removed when the windows were blocked up. The guy making the windows has offered to put in wooden sills, which I can't imagine would last very long. As the other windows have stone sills, I think it would look better to either get replacements to match them, or else not to have any sills in the two reopened windows. However, getting matching sills would cost us in time and money. Is it ever okay not to have a sill in a window, or do you run the risk of too much water entering into the house walls? (Our walls are random rubble limestone, and will eventually be rendered). Any advice would be greatly appreciated.

Finn

 

[Gervase]

Sills are a good idea, both aesthetically and to keep water off the wall, so I'd be tempted to replace them. Plenty of windows have wooden sills, but if you've got rubble-stone walls that suggests that your windows are recessed a fair way, and that stone sills would be better.
Ring around a few quarries and cost them - sawn soft limestone shouldn't be too exorbitant.

 

[biffvernon]

You've got to work out where rainwater that hits the window and runs down is going to go. It must not run on to the top of an unprotected wall as the water will then flow through the wall and half of it will emerge into your room. That's what the sill is for. You may be pleasantly surprised at the low cost of getting a stone sill made to your size if you choose the right stonemason. A wooden sill can be perfectly satisfactory, water proof-wise, if it sticks out to allow drips to miss the wall below, but the design is not always appropriate to an older building. If it's made of oak it won't rot in your lifetime. Putting some other waterproof layer on top of the wall below the window frame is the other solution. Tiles or slates, slightly sloping down and outwards, is a common arrangement. A piece of the black plastic damp-course sheet, hidden neatly within lime pointing or burnt sand mastic is a cheap alternative.

 

[finn]

Thanks for the advice, Biff and Gervase. We'll look at getting stone sills made, and if it's too expensive, then the slate dpm sounds like a good idea.

 

[thiambal]

A couple of possibles - sure there are many more

http://www.blackmountainquarries.com/

http://www.masonrysolutions.co.uk/?gclid=CLqM_KnW0IcCFSR0EQodYQEJGA

Though my gut feeling is to stay clear oif any company with the work Solutions in its title! :wink:

 

[mark_j_k]

What size sills do you require? I have got several old stone ones lying about the place.