Hello,

I am new to this forum. Please excuse me for not knowing the right words for things. I am having a 2x4 Velux skylight installed. My roof is pitched, not flat. I have a flat drop ceiling. The opening in the ceiling was cut to 4x6, with the intention of having all 4 sides of the shaft flared out for maximum light. Now the installer is saying it can't be done the way we planned; he wants to flare the top and bottom, and keep the sides straight. I know I have read about skylight shafts with 4 flared sides - they are described as challenging, but doable. But I can't find any detailed diagrams or instructions. So my questions are: has anyone here done it? Can anyone point me to a description of how it's done? Anything that would help, even a diagram or photo. Thank you.

 

lavamom,

Welcome to the forums.

It can be done, but it is certainly a challenge!! I did all 3 of mine that way. two of my skylites are the same -- 2X3 curb mounts. The ceiling opening is about 3' X 4'. The shaft wall on the low end is vertical. The side walls and the high end wall all slope. The high end wall is easy. The side walls took a lot of time to figure out.

Start with a piece of plywood cut to length and slid it up into the shaft, cutting into the waste as you go, until it fits into the side. (Once you figure it out and it fits for one side, it becomes the pattern for all of the other walls that are that size.) What you will end up with at the very top of the shaft is a little pie shaped piece on each side. Mine are about 2" wide at the low end and taper to nothing. You mark lines and frame it to the lines. The sheetrock for the sides will be flat (not bent).

 

Thanks for taking the time to respond Lefty. I am impressed that you accomplished this, now that I see what is involved. We basically gave up for this skylight, and will just taper the top and bottom and go with vertical sides. I was interested by your reply, because it answered a question I had - can this be done with only 4 flat planes? ANd from what you said, it took you 4 large planes, plus 2 small pie shaped ones. We didn't think of that, I wonder if it would have worked in our setup. The installer is a bit fed up at this point though. Thank you.

 

I perfectly understand that the installer got fed up. Trust me, I DID TOO!! But, my wife got her whip out... Three days later, (plus a couple of 6-packs and a lot of new words) I stumbled across the solution.

You're the customer -- get what you want. But now that you realize just how involved it is, you'll understand why the installation bill WILL be bigger. And feel free to have your installer post in here, and I'll do what I can to coach him. Or PM me and I'll shoot you my email address. He and I can talk that way too.

I'm totally happy with the way my skylights came out, and now that I've lived with them for about 20 years, and having seen so many others that settled for straight shafts and how much less light they have, I'm glad that my wife was so persistant!!

 

Did he give a reason WHY?

Such as... trusses which cannot be altered, or some other unmovable obstruction?

 

GOOD CATCH XSleeper -- the TRUSSES!!

I didn't think of that, but IF you have trusses, they can't be altered. (Well, they can, but that would require a truss engineer coming in and telling you how!)

My house is just 60 year old hand-stacked joists and rafters. Nothing about them is engineered (THAT'S another horror story in some of the floor plans in this subdivision!!), so the fact that a joist and rafter ran right through where the skylights had to be just added a little extra to the permit and framing involved.

 

Sorry to be delayed in posting a reply. To answer the question, the reason he couldn't do it was not trusses. It was simply that no one could see how it could be done. Part of the problem was timing - he didn't realize it was so complicated until after the hole in the ceiling was cut and framed and he was actually holding the cut piece of driwall and trying to get it to fit. If this had come up in the planning stages I could have researched more and pushed to get it to work (and emailed with you Lefty - thank you for that offer). I watched as he tried to fit the driwall in, we called in the GME to assist, I googled everything I could find - but in the end there was no way that we could find to do it with 4 flat planes and a rectangular ceiling opening. He thought it could be done with a trapezoid ceiling opening, or in a scenario where the ceiling is parallel to the roof line, or possibly with a square skylight. But as I watched him try to fit shapes in the space (we finally used large cardboard cutouts to make it easier than heaving driwall around) it seemed undoable. The top and bottom of the shaft taper easily, because their horizontal edge is parallel to the roof. But the horizontal plane of the sides of the shaft is not parallel to the changing pitch of the roof line, which is where the challenge comes in. It isn't obvious until you actually see it. It's a bit hard for me to describe the geometry of it, and I didn't understand what the installer and GME were saying about distorting the driwall and the shapes twisting - but I could tell visually that it was complicated. They kept saying we would end up with a distorted shape. I hope this is making some sense.

We have another room where I think we will eventually put another skylight, and for that one I would like to achieve the 4-sided flared shaft, which is partly why I posted this question, but I also thought it would be useful for others to know. I was hoping there would be time to fix my immediate situation, but it didn't work out that way. It's a bitter pill - the two tapered sides cast the light out really nicely, but the two vertical sides just shoot it down.

Thanks for the advice, and thanks Lefty for offering to work with the installer. Are there any other forums you know of where I could post the same question to hear from more people who might have run into this?

 

lavamom,

I've been there, done that, and I know EXACTLY what your installer and the GME were facing. It's too bad that they weren't able to stuble across the solution. But all is not lost!

You are planning one more skylight and would like it done with all 4 walls of the shaft slanted. My offer still stands -- PM me your email address and I'll shoot you a picture of one of my shafts. I'm sure that once your installer SEES the finished shaft, he can duplicate it. (And it wouldn't be that difficult to get back and redo the other 2 either -- all the hard work has been done!!)

 

Ok, I will PM you - thanks!