Flat Roof Design With Loft

[whit]

Just curious, has anyone built a Builders Cottage with a flat roof that includes a loft?

[MountainDon]

I don't recall seeing one done, but it would be possible. How much loft headroom are you thinking about?

[whit]

I guess I would need about 6 feet head room at the highest point.  I guess I'll have to sketch something to see what is possible. Just though maybe someone attempted this as the roof would be easier to construct.

[whit]

Here is my sketch up of the 14X24 flat roof with loft. Comments anyone 

[Don_P]

There's no headroom and the floor thickness isn't in there yet.
Lapping over a beam on top of the "center" row of posts would take care of it. It really isn't more complicated at that point to raise the mid posts to form a peak and run the rafters down from each side of the ridgebeam. One to a 12', or 14' wall the other down to a 10' wall. Course then it really needs to be more like 24' square to look right.

[whit]

I took a look at the 14X24 plans and realized I had my sketch reversed. I had the width as 24 and length as 14. In the plans, the width is 14 and the length is 24. This new sketch makes for an easier flat roof span of 14 feet plus 2 feet either end. Sorry for the confusion. 

[whit]

Here's another sketch for a 14X24 with a loft where you build two flat roofs. One over the loft and one over the rest of the building.

In this design, the framing for the first level would be done at standard 8ft height with the exception of half the wall for the lower part of the building. It would be framed at 10ft to allow for the lower sloped roof. The loft would be framed with a higher front wall, 8ft and a lower back wall, 6ft to provide for the roof slope. It would be framed right on top of the subfloor for the second level.

This way you are getting full head room on the main level and pretty good head room in the loft. My only concern now would be the weight on the the foundation on the loft side. Not sure if it would be too much for the foundation.

It's probably a little crazy but just I'd share my thoughts and if anyone had any ideas or have built or come across such a design.

Cheers!!

[John Raabe]

The Little House plans are set up so that all the bearing is on the width of the building (10, 12 or 14' wide). A shed roof spanning that width does not have a real chance of a loft with headroom unless you raise the wall heights on both sides. When you change the roof span to the long dimension (length) of the building, you not only need to get long span rafters but you also have to design the foundation and walls under each end to carry the roof loads. These walls are very lightly loaded in the Little House design.

[whit]

Thanks a bunch John. I had a feeling the rafters were getting too long and that the physics of the whole thing was changing the load on the foundation. I have your Little House plans and I really like the designs. I'm probably going to go with the Builders cottage when I get around to clearing the land. Still too much snow up here in the Great White North.

Thanks for the help.

Cheers!

[whit]

This design is something I am thinking of.

http://countryplans.com/smf/index.php?topic=7610.0

[John Raabe]

I see where you want to go. There is a pretty complete plan in PDF format at our sister site PlanHelp.com (membership site). Check this list and scroll down to "26x30 Double Shed Cabin":

http://www.planhelp.com/public/programs/downloadsearch.cfm?searchtype=simple&searchmode=cat&keywords=recent&sortby=name&cat=3DHA%20Plans



I have not sized the beams in the PDF plan - you will need to check those for your snowloads. Aso, if you extend the walls higher to get an upper floor over the taller section, that will change the loads as well. You also have to fit in the stair, of course.

Here's the info on this download that a member sees:

[whit]

That's exactly what I was thinking!   Putting two of your 10X14 designs together, side by side, each with a sloped roof. One side would have the loft (or entire second floor), the other would remain wide open which would make for nice high ceilings.

I'm thinking a cement post and pier foundation sitting on 30" footing tubes as a base should probably handle the load quite well, especially on the higher side. A pit dug down as far as I can go (48") for each pier back filled with crushed stone should do the trick of keeping the frost at bay. The area I want to build on has the advantage of sitting on solid rock so I may not have to dig that deep but frost is definetely a problem in my area.

At a cottage I belong to, I have seen 16" circumference concrete piers, four feet to five feet high be moved by the frost and buckle underneath the cottage. They were reset and back filled with four inches of crushed stone and they seem not to be moving. We hold our breath every year when we go up in the spring to see if the 75 year old cottage has moved.

Since I will be building about two lakes away from this place, I don't want any heaving happening.

These plans look good John and I'm gonna grab a download of them.

Just for the record, I have to pass everything through an architect in order to to build in my area.

Cheers

[John Raabe]

Whit:

You seem to have spotted the potential issues with your foundation, and your architect will be a good resource on your foundation and soil issues and may also be able to help with beams and customizations to your plans.