Skylight Size and Placement
We are thinking of adding a skylight to the living room on the 4th Floor. There is currently a ceiling light in the middle of the room, where it would make sense to put the skylight. The room is pretty much square shaped. If we were going to put in a skylight: 1. What do…
We are thinking of adding a skylight to the living room on the 4th Floor. There is currently a ceiling light in the middle of the room, where it would make sense to put the skylight. The room is pretty much square shaped. If we were going to put in a skylight:
1. What do we do about the beams supporting the roof? Is it OK to cut them for a 3×3 if we do appropriate interior framing?
2. Where should we put the skylight, if not in the center of the room? Near to the wall with the window to the front of the house? Or near to the wall where the door is?
Thanks!
Thanks WR and Edifice. I also heard from someone that if I couldn’t place the skylight in the middle of the room (which I can’t because the light is there) the skylight should be placed near the southern wall so that the light will come in to the entire room. Thoughts? The building faces north-ish, the room is in the front of the house.
I agree with all that WR says.As a practical matter the joists are stiffer closer to the masonry walls, if your roof is strong you could probably cut and head off one joist near the edge, more than that and you are looking at substantial structural work as WR stated Check what the joist spacing is, many skylights are made for 16″ and 24″ spacing so no real structural work is needed. It is much easier if you can live with a rectangular skylight.
It doesn’t sound like you should have too much trouble installing a small (3×3) skylight in your top floor ceiling. We’ve done many skylights in our time and they invariably transform the rooms into lighter brighter more inviting spaces.
Without seeing your space I can’t really advise you where to place it, but you should think about how the space will be used. Some people like to sit directly in the sun (especially in the winter), while others shun it. Remember that direct sun will come through the skylight, so you don’t want it too close to a TV or computer as it may make it hard to see the screens. Of course you can install a blind across the opening, but they tend to be a little hard to maintain.
The most important thing to do from a structural point of view is to carefully evaluate your existing condition before you start. The roof’s waterproof membrane and the underlying support framing are the crucial items here. If the roof is very old, has many layers laid over each other, or shows signs of having trapped air bubbles you should be careful about disturbing it. Bubbles are a sign of trapped moisture which may well find its way to and through your new skylight.
The roof framing has to be bridged (headed-off in construction parlance) once you’ve cut out the joist or two necessary to fit your new skylight. This bridging means that the adjoiing joists must now carry the load previously carried by the one(s) you have cut. If the roof is sagging or is very bouncy (go up and jump on it) you may want to think about abandoning your skylight idea, or if you are bolder, reinforcing (doubling) the adjoining joists to take the additional load. Interior partitions or posts could be introduced to brace the roof, but remember they have to rest on something and that area has to be strong enough to take additional weight without sagging.
Hope that helps.
Will Rogers Architect
212 524-8590