Ahoy! Roof Experts

[ChiefChris]

The roof I have pictured in post #51 has a 2x10 ridge with 2x12 rafters, the ridge is broken into 4 sections of 16' each. There are collar ties at 48" laterally - 14' off the floor - only 36" from the peak. The flat ceiling is only there for lights. All 3 dormers across the front are bearing on double rafters on either side into the ridge. The only bearing is front to back....

In fact - the ridge doesnt go all the way through as it breaks for 6' within the cupola....

[George Godwin]

In post #56, my proposal would eliminate a shaft that involves structural adjustments on the ridge and roof. The Cuppola would sit on the roof and the Sun Pipe would go between the rafters or trusses as normal for its installation. It seems to me that the structural shaft is not worth the trouble since the Cuppola approach is very inefficient in terms of heating, cooling, and light transmission. But I think that I am talking to myself on this one.

[Allen42acj]

Hi George
I like that idea of using the tube rather than the cupola for light..
Never seen them used for more than decoration or ridge venting..
Not sure how good they would work if you hid it inside a cupola..

[George Godwin]

Allen, - Thanks for your reply. My thinking is that a cuppola with a 6' shaft downward as in Chris' images is a poor and out-dated design in this day and age of energy conservation. It is also a framing challenge on the roof structure that is not worth the trouble and it does not transmit light efficiently. That is why I was indicating an alternative approach. The Sun Tube dome could be outside the Cuppola or even mounted on its roof since its a long way up and no one could see much of it anyway, even if they were looking. A cuppola with windows and shaft (what is known in these parts as a Belvedere skylight) is a rare structure and an arcane design that needs some re-thinking from an energy waste and light transmission efficiency perspective in my opinion.

[Allen42acj]

George
It might not be my first choice to use,but it does look good.A little bigger with a way to get up there and I would like it more..Bet it was a lot of work and extra labor to do it..
I have not seen one of those tubes in a house yet..

[George Godwin]

Allen, - For Sun Tubes, see some websites as follows:

http://www.sunpipe.co.uk/sunpipe/domestic/index.php

http://www.sun-tek.com/Tube.htm

http://www.bigfrogmountain.com/suntunnel.html

http://www.veluxusa.com/solar_tube.htm

An image on Sun Tube light coverage is attached and also an image of a Belvedere Skylight being built locally.

[Allen42acj]

George
I have seen them in pictures and lumber yards,just never installed in a real house..Looking up and thinking though,little more light in here..
About time to cut a hole some place here..

[louis]

We use sun tunnels all the time here is the South.

[George Godwin]

Allen, - They are great for interior Laundry Rooms and Hallways that need light. You can fit a light fixture in them for at night. Saves electricity in the daytime and they are energy neutral. In contrast, the cuppola (Belvedere Skylight) is a backward design. It can be attractive on the exterior and in my opinion, should just sit on the roof like a normal weathervane cuppola. It would be better to use a Sun Tube for the lighting value inside the structure.

[Allen42acj]

And they fit between rafters if you want..
I would go with velux I think..They have very good skylites..

[George Godwin]

Louis, - Where in the house have you been using them and have you done more than one in a single house?

[ChiefChris]

I just have to say - I agree with George and all of you on the sun-tube idea...however on this particular job the cupola isn't there for light, but for the visual accent on the exterior, with no regard to efficiency. Just looks.

The client is not interested in cost effectiveness, budgets, or any of that - just the way it looks when it's done. The images of that project are of a seasonal pool house with a 5 car garge on the lower level...cost is currently over $800,000 - and rising (they already have a 4 car garage on the other side of the estate). I am also designing a deck for between the garage/pool house and existing house that is currently between $180,000-$200,000. She just put a new living room suit that was $220,000. In their dining room, they have 6 placemats on the table that literally were $2,500 each. The ceiling beam in the image showing the light fixture a few posts ago (I designed in Chief sent drawings to the mill for production) was $10,000 and there's 2 in the great room.....

All I am saying is that for this particular project - we're not concerned with the light (or lack of light) coming in through the cupola...it's strictly there for the look on the exterior and to hold the 450pound chandelier.

[rgfeher]

$2,500 for a table place mat? Geez, isn't that a bit extreme? I guess if the dining room table can be viewed from the $220,000 living room suit, one has little choice. And here I thought $48,000 for German made cabinets placed in a garage was more than a touch too much.

The solar/sun tubes work better than I had anticipated. It is surprising the amount of light they transmit. Must have something to do with light refraction through the tube tunnel itself. They are exceptional vehicles for providing natural light in interior areas. Also, the tunnels are flexible to a degree, eliminating the framing considerations of a skylight (for the smaller ones that fit between rafter centers).

Most of the work I do is renovation, so when I add an addition that now blocks the natural light that perhaps the kitchen window had supplied, that area's ambient light takes a beating. Short of placing a skylight(s), that area has no access to natural light. Many times, with a roof overlay, skylights are not an option due to framing and valley considerations. This is one area solar/sun tubes are especially valuable.

[louis]

There is a lot of excess in this world. There is a house being built here that is 35,000 square feet and is for 2 people. No kids and no kids in the future.

[rgfeher]

Louis,
As each of us needs his/her own space, perhaps they're planning on another type of future. That much area certainly could provide it for more than two. It never ceases to amaze me. Excess to the point of ludicrous.