The Builder's Cottage

[DavidLeBlanc]

I have just a few questions about the Builder's Cottage  please!

Looking over the Echilada Kit, I don't see any reference to a perimeter foundation or a basement foundation. There's some mention of a slab foundation with perimeter for Victoria's Cottage though. I'm asking because I know that in some  jurisdictions (Humboldt County, CA), at least at one time, pier foundations where not permitable due to earthquakes (aside from which, if I can afford it, I'm going for a full basement). What's the scoop?

If you build the BC with 12' sidewalls (roof peak @ 22'), how far out would the roof extend if you brought it down in a straight line to   either 7'6" or to 6' above the floor deck level? ("Bumps" roofing is the intent, and I want to retain the same roof angle.)

How do some designs get away with not specifying collar ties in rooms with cathederal ceilings?

Across the 14' axis of the BC, could one put a ?rim? joist (I wouldn't know a rim joist from a duck billed platypus for sure! ) inset from the long axis of the house so that some part of the width of the house along one side of the loft is open to the roof rafters? (here, I would think that some sort of tie, 4' on center from the perimeter wall to this new inner wall (think of the photo that illustrates the solar kit window wall), would make sense). Would it be necessary to add some sort of structural reinforcement to the outer corner of the building?

Can the 24' length be increased to 32'? What would that do to the 'fast permitting" characteristic of the BC as you ship it?

Do SIPs cost the same, more or less than site built, site insulated walls and roofs? How about a hybred where the walls are stick built (sounds like it would make for easier electrical and plumbing install) and the roof is SIP'ed?

[jraabe]

The Builder's cottage plan (included in the Enchilada) has a concrete perimeter foundation (crawlspace). This can be upgraded with an 8" wall and 8x16 footing for a basement (you can do this with callouts). Many places in CA will require an engineering review of any plan. This is when you can make your modifications.

The structural cross section is the 14' width and can easily be extended in length.

The roof is at 45º so for every foot you extend it out you go down a foot.

The loft joists tie the rafters together and in the open section of the cathedral ceiling there are rafter ties at 48" which look like exposed beams.

SIPS are considerably more expensive than stick framing but might save on labor costs. The SIP manufacturer will do their own engineering from your plan modifications.

[DavidLeBlanc]

Thanks for your ever-helpfullness, John!

I know what collar ties are and what they're there for (counteracting the desire of the roof to fall down flat by pushing out the walls), but I've seen lots of smaller and bigger designs that don't have them. Is there a secret?


In this pic, looking down the long, 24' (+) axis of the house, imagine that the beam in the upper left corner is the egde of a BC's loft area and the beam to the upper right is part of the outer wall of the house. I could do something like thjis in a BC, couldn't I? Is there a way to minimize the vertical size of those cross members that join the inner beam to the outer one? One function of this space is the entry way and the other is a library/den, maybe with high bookcases and a french door with sidelight on the short end. Small skylights would allow dappled light to filter down (oh, la, la! dappled light! ). I'd like to have more sense of opennes - span would be ~5'. The roof will carry down to the right to create a 5' bump, effectively making this an approximate 12' x 10' room.

Sorry, this post got cut off earlier by an acute hypoglycemic incident, requiring the instant consumption of jam straight out of the jar, followed by a 3 hour nap!. John, I hope you won't mind revisiting your answer!

[jraabe]

Yes, assuming we are looking down the length of the building, the rafter ties (I would do dbl 2x8s w/ 2x4 @ center) would look much like the beams shown above. They would be at 48" o/c locking every other rafter.

The other way to do a cathedral roof is to carry the ridge weight with a ridge beam. Then the load on the wall is only downward and you don't need collar ties or rafter ties.

This is what is done in the Victoria cottage plans.

[spinnm]

And, David, a lot of cathedral ceilings that you're looking at in pictures are done with engineered trusses which don't require collar ties.

[DavidLeBlanc]

The other way to do a cathedral roof is to carry the ridge weight with a ridge beam. Then the load on the wall is only downward and you don't need collar ties or rafter ties.

It literally never occured to me that the BC didn't have a ridge beam! How hard would it be to have it use one of those, at  least over the living room?

Shelly's suggested alternative of using engineered trusses - sounds like a lot more money?

[jraabe]

The 2x ridge board could be recalculated to be a structural ridge beam and you could then eliminate the 3 rafter ties/beams that run across the open cathedral area. This beam needs to be sized for the snow loads and must have support at both ends. In the Builders cottage it wouldn't have to be huge. Maybe 2 LVL beams spiked together or a glulam.

As far as engineered trusses go they are not very expensive. A scissors truss would be the most common solution but you can have attic trusses done for the loft.

[DavidLeBlanc]

Slightly confused - mostly by not really knowing what a scissors truss or an attic truss looks like. I thought scissors trusses had a horizontal component that meant a flat ceiling. I'm only guessing that an attic truss are those that have 2 parallel lenghts of wood joined by x-bracing along their lengths? (Really do have to study up on framing taxonomy - only know a very little).

Who would do the engineering to convert to a ridge beam - and how much would you charge if you were willing to do the work?

P.S. Would you mind reviewing my changes to the post that's illustrated with the sunroom, above, and see if you have anything different/additional to say? You'll see the reason why there - I was interrupted!

[jraabe]

Anytime you do modifications to a plan you should have them reviewed locally. My engineer charges $300 for his review (and stamp if required by Bldg. Dept.)

Get a list of all the things you want to change and have them reviewed at the same time. As the booklet in the plans set says you might want to schedule a presubmittal with the inspector to find out any local issues there.

You will want to contact a local truss supplier to find out what they can produce. Here are some examples...

Scissors truss: http://home.howstuffworks.com/house9.htm

Attic truss: http://www.timberframe.co.uk/attdorm.html

[borgdog]

I personally love attic trusses over garages.  Gives wonderful storage space, and if the roof pitch is high enough and garage wide enough, I've seen shops, rec rooms, play rooms, etc put up there.  The sad part is for the average garage it is not much more expensive, but people just don't think of it, or the builders don't care and want to save a couple bucks.

[DavidLeBlanc]

After looking at the truss examples, I'm leaning towards the ridge beam.