Roof lights - best configuration

adocholiday

Hi all,

Really straightforward question here. We are currently designing a kitchen extension and we have vaulted ceilings. Dimensions of the room are roughly 8.5m wide x 6.2m long and 5.3m from floor to apex of the ceiling.

The room is South facing but there are no windows/doors facing that way, only East so the room is very dark. We want to put some south facing roof lights in to maximise the light. Just wondering would it be better to put one large roof light in (say 2m x 1m) or 2 smaller (say 600mm x 900mm)?

Not just from a light perspective but also thinking about things like air tightness etc. A larger roof light would mean less cuts in the roof but 2 smaller ones might be better for light. Also any structural considerations etc.? Just a standard 40 degree tiled roof.

Any feedback welcome!

JimmyMW

adocholiday wrote: »

Hi all,

Really straightforward question here. We are currently designing a kitchen extension and we have vaulted ceilings. Dimensions of the room are roughly 8.5m wide x 6.2m long and 5.3m from floor to apex of the ceiling.

The room is South facing but there are no windows/doors facing that way, only East so the room is very dark. We want to put some south facing roof lights in to maximise the light. Just wondering would it be better to put one large roof light in (say 2m x 1m) or 2 smaller (say 600mm x 900mm)?

Not just from a light perspective but also thinking about things like air tightness etc. A larger roof light would mean less cuts in the roof but 2 smaller ones might be better for light. Also any structural considerations etc.? Just a standard 40 degree tiled roof.

Any feedback welcome!

If it were me i would not face any roof light south as this is when the sun is the highest in the sky, therefore the direct sunlight will be very blinding for a large portion of the day, if you are looking for light alone the most consistent light will be from the north imho, the larger the roof light the better but velux type systems only go so large and once you go into bespoke systems its big money. I have a 1.8m*1.3m roof light facing north in my kitchen with a vaulted ceiling and it is fantastic for light. FYI note as far as i am aware a roof light will provide approx 70% more light than a vertical window of the same size

looksee

JimmyMW wrote: »

If it were me i would not face any roof light south as this is when the sun is the highest in the sky, therefore the direct sunlight will be very blinding for a large portion of the day, if you are looking for light alone the most consistent light will be from the north imho, the larger the roof light the better but velux type systems only go so large and once you go into bespoke systems its big money. I have a 1.8m*1.3m roof light facing north in my kitchen with a vaulted ceiling and it is fantastic for light. FYI note as far as i am aware a roof light will provide approx 70% more light than a vertical window of the same size

Generally agree with the above. We have south-west facing lights and while they are great for a lot of the year, the room is difficult to use in summer sun. I will be putting up shades before the summer this year. While this is of course an option it does negate some of the argument for having the lights in the first place. I would not say absolutely don't do it, but do make allowance for the fact that too much sun in summer can be a liability.

adocholiday

Thanks for the advice. Our issue at the moment is that the room is very dark, we have to put the lights on every time we use the kitchen regardless of how bright it might be outside. This is despite having a large East facing sliding door & window and a small south facing window above the sink. We live in a valley surrounded by trees which doesn't help.

Even though we are putting in a floor to ceiling gable window it's still going to be east facing and I'd be concerned that we won't get enough light from north facing roof lights. It's very hard to know what the right move is here.

Calahonda52

hard to understand how a room can be south facing, last time I looked my rooms have 4 walls, each on a cardinal compass point.

Any, consider going for a lower pitch mono slope roof rather than the vaulted version and fit the roof windows away from the south.
You could use engineered or CLT roof joists for that span, also consider decrement delay when picking your roof insulation

Dudda

It's hard to get a real accurate feel for how dark it currently is without seeing it and therefore giving the best advice. Placement of the rooflight is key. For example if you've a large central kitchen island a rooflight above that could be very good.

It's a bit overkill for a kitchen living room but you can get a lighting analysis done. The room is built on a computer in 3D and trees outside or other shading added. The software works out the light value for every inch or the room. We get it done on a lot of our commercial projects but never did it for a house. You'd probably spend 500 which would go a long way on a rooflight.

JimmyMW

adocholiday wrote: »

Thanks for the advice. Our issue at the moment is that the room is very dark, we have to put the lights on every time we use the kitchen regardless of how bright it might be outside. This is despite having a large East facing sliding door & window and a small south facing window above the sink. We live in a valley surrounded by trees which doesn't help.

Even though we are putting in a floor to ceiling gable window it's still going to be east facing and I'd be concerned that we won't get enough light from north facing roof lights. It's very hard to know what the right move is here.

I get loads of light for the north facing roof light, I will try to take a pic over the weekend to show you, however i am very glad i did not go with the south facing as i would be blinded for 5 months of the year

JimmyMW

See roof light in north facing orientation on a fairly dull day, i feel it provides plenty of light and is never blinding