20X34 floor plan idea- need feedback

[MushCreek]

 I got my 2 story Universal plans yesterday- Thanks, John! The plans are great, but like most folks, I have specific needs that call for changes. I'm building on a hillside, on a walk-out basement. The downhill side, and the pretty view, is to the left in this pic. The garage has to go on the uphill side, and the entrance needs to be where it is, due to the lay of the land. What I did was take the 20X34 2 story, put an 8/12 pitch roof on it, and extend that roof all the way down to the garage, making a salt box design. It's a happy coincidence that that roof pitch yields just the right height at the garage eave. I extended the nose of the garage to add architectural interest, and to allow for a bigger room behind it. The garage and den behind it would be on a slab, although I'd build the den floor up to match the floor levels. The main house would be on a walk-out basement.

There's one potential problem- my property isn't that steep. In the 20' width of the basement, it would only drop about 3-4' as it sits. The result will be that the house will be WAY out of the ground, or more excavation, and retention walls will be required to sink the house in to a proper depth. I could go with a crawl space, but i don't want to deal with the mold, rot, and critters that seem to plague homes in the deep south. Besides I want a basement for storage, and to make servicing the utilities easy. I could extend my siding down further to hide the exposed foundation, but the porch would still be way up there, and the garage might end up being several feet lower than the house- not good if one of us is ever incapacitated. I kind of like the idea of retention walls, and a nice flat area outside the basement to set up my outdoor kitchen, but I'm worried about the cost, and what problems such a layout could lead to. Any opinions on the floor plan, and how to go about grading the site?

[archimedes]

I don't know much about your grading questions,  but if you end up having to do a crawlspace,  you could do an enclosed and sealed crawl space and avoid the mold and critter issues.

http://www.crawlspace.net/?gclid=CMjZwO3E6qUCFYXu7QodjkuhoA

[bayview]

   In your situation, you may want to consider an insulated crawlspace with a concrete floor. . .    Properly installed with drainage, a sump pump, vapor barrier and insulation.   With special attention to the insulation in the outside walls.   Heat and air condition the space and you won't have any problems with mold, etc . . .    (Do not insulate the flooring between the crawlspace and the first floor)   Add a vent stack if radon gas is a concern.   The concrete floor will allow a space for storage, furnace, water heater and other utilities.

  I have seen vented crawlspaces with a vapor barrier placed over gravel on the ground.   Drainage is installed in the gravel to a sump pump.   Generally the space has numerous vents around the foundation.  But, sometimes the outside air is drawn in and exhausted with a fan  The outside air is drawn over the cooler plastic vapor barrier causing condensation.   A perfect space for mold, mildew and wood rot.  

  The garage could be a slab and tied into the homes crawlspace.  

http://www.buildingscience.com/documents/reports/rr-0401-conditioned-crawl-space-construction-performance-and-codes/view

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[Native_NM]

How about two blocks of Polysteel PS4000 ICF on footings?  The blocks are 24" high;  two blocks would get you to 4'.  They also make 16" blocks, which could get you to 3.33' if needed also.  Pour a slab between the blocks and you have a nice, insulated crawl space for utlilities and storage.  On the other hand, depending on the excavation costs, it would be a shame to only have a half basement.

I watched some owner/builders build with Polysteel ICF in North Albuquerque Acres.  I talked with them on a few occasions, and they said it was as easy as building with Legos. 

[John Raabe]

I think your plan sounds workable and I assume the general grade is such that you might have an approx. 4' high basement foundation wall cut into the downslope side. That could be topped by a pony wall where you could have windows. Some part of that downslope side could be widened and graded out to near level to provide a patio area with walk-out access to the basement. You will have some cut and fill work to do with a dozer and/or foundation contractor. This will be well worth getting the right help to make sure all the levels work out. You do not really need big retaining walls for this. I expect the slopes can be smoothed out and perhaps terraced by stepped landscaping timbers or pavers. This work could be done later.

Start at the high end of the house and get the garage slab and den foundation set high enough and with proper drainage around either side. Then work your way down the floor levels to the where the basement floor and patio level can be determined. From there the footings and backfill areas fall into place. You may want the help of a local home designer with this. Someone who can shoot the site elevations and help with the roof shapes.

Working on a slope is more involved on the design and foundation build but almost always provides much more interesting spaces both inside and out. Work up all four elevations with the additions and basement and make sure they work well with your site plan.

I like the way you worked up a saltbox on the roof. A gable end on the garage front should work. Draw up the important front elevation carefully and see what works best for the porch roof. Also have your site plan in mind so you know where folks will park, turn around, and how they get to the entry.

[MushCreek]

I agree- it seems a waste to build half a basement. Since the house will be small, I had always planned on a basement all along. You'll notice that there isn't that much storage on the main floor, so we will need the space. I am going to contract out all of the excavation and footing work. I'm thinking ICF basement, which I will stack and brace myself, but I have an experienced ICF guy that will supervise the actual pour. I'll have him shoot the elevations and discuss strategies and costs.

I've drawn a 3D view, and it gets weird where the porch and garage roof meet. I can either leave a gap between them, or create a valley where they meet. If I leave a gap, I'll need a gutter to keep from pouring water directly onto the porch! It's true you won't be able to enter the porch from the front unless I build steps, since the ground will be falling away. I might have to extend the porch, or push the garage back a bit to have room to enter the porch from the side.

As drawn, we can build the shell and finish the main floor first. We can set-up house there, using the den as a bedroom (that's a closet at the garage end). If money is tight, there we'll stay. If funds allow, I'll finish the upstairs, and we'll have the master up there until we're too feeble for stairs, at which time we'll move back to the main floor. That's why I want the room behind the garage; it's our Plan B should either of us lose the ability to negotiate the stairs safely.

As for developing the rest of the site- when they create the flat area for the garage, I'll have them cut into the hillside to create a driveway alongside the garage, so vehicles can get past the garage over to the barn, which will be on relatively flat ground about 100' away. There will be plenty of room to park and turn around by the barn. I'm still trying to work out how to turn the car in the garage around. It seems convoluted to back out, drive past the garage up to the barn, turn around, and then drive out. When they're pushing dirt around, I suppose they could create a spur to back into. I have a friend with similar land, and that's what he has.

[John Raabe]

Sounds like a plan!

For a site with the slope you describe, I think a basement is a good investment. Especially in a smaller house. (I wish I'd done one in my house - and my site is basically flat.)

[MushCreek]

It just occurred to me that digging a hole deep enough to sink a 20' basement is the same as the hole I would have needed for a 40' basement. The only difference is whether I'll need retention walls, or if it can just be graded.

[bayview]

   A basement with a two story house and an attached garage?   Have you considered a larger split level?

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[MushCreek]

I forgot to post an isometric view of this idea. I think it makes for a nice looking cabin, and could be sited for good solar gain on the high side. That isn't an option for my site, but we're in a mild climate. As you can see, I didn't quite work out the intersection of the porch and garage roofs- I know what it needs to look like, but don't know how to make SketchUp do what I want!

[John Raabe]

That looks pretty good. I don't know how to extend it in SketchUp either but you carry the porch shed roof over to the right until it forms a valley with the garage gable.

[Don_P]

That's the easy way, pull it through to form the valley, draw in the intersection and then delete the overlaping "junk". My Sketchup for dummies just arrived today so I'll probably learn that everything I've done is wrong