To skid, or not to skid?

[youngins]

Hello,

I am in the process of drawing up plans for an 8' x 12' version of the "Little House." We plan to use the skid foundation, but ran into a possible snag.

Where we want to layout the 12' side of the structure makes it perpendicular and run through the middle of the drainage grading. Using skids would affect proper draining past the structure. Putting the skids along the short (8') side would mitigate the problem but then we would need to use 12' joists running between the skids, in addition to other possible structural issues.

Is there a technique for solving this problem? Or, is using a skid foundation not appropriate for this situation?

Thanks for your comments in advance,

Chris

[John Raabe]

I'm not sure what you mean by "run through the middle of the drainage grading" - is this something you would need to span? Can more drainage rock be put in to allow drainage below but still bear the skid?

[youngins]

I'm not sure what you mean by "run through the middle of the drainage grading"

PLets see if I can explain.



The red line depicts the Fire Marshalls setback requirements for accessory buildings (3 feet from side and 10 feet from rear of property). The blue arrows represent how the landscape is graded - ie the valleys in the landscape which allow drainage of water from the property. As you can see, the structure (in green) is situated to cross the path of the drainage path.

Because of the "valleys", I will have to build up more gravel in the middle than on the sides to make the top of the gravel level from end to end.

Can built up gravel for a skid foundation act as a dam, thus pool water. Is their a technique to over come this potential issue?

Thanks

[John Raabe]

For an intermittant flow you could put in a small culvert and just put crushed rock on top of it (leave it open at either end). The rock will still bear fine for your lightweight building. You're making a bit of a rock bridge with a hideout for the trolls  .

[youngins]

OK- we will incorporate it into our plans and see how it works out.

We don't see a lot of chat regarding skid foundations in this forum - so we were wondering if this is one of those things people just don't put a lot of stock in.

Thanks

[glenn kangiser]

Most of the houses built here are permanent dwellings so about the only time we have discussed skid foundations are for cabins that are planned to be moved or smaller utility buildings.

Most banks and permit agencies want a permanent foundation.

[youngins]

Gee- I thought you were going to make some off the wall comment about people's obsession with concrete.

[glenn kangiser]

I'm the earth dwelling troll John warned you about - you just never know what to expect. :-/

[John Raabe]

A skid foundation per the Little House plans and set on a well drained gravel pad will last as long as the building it supports. This isn't what you would want to have for a habitable building for the reasons I mention in the plans.
• You don't have access to the underfloor area so you won't be able to install and repair wiring, plumbing or insulation.
• The building will ride on top of any freeze thaw cycles in the soil so it may not stay plumb and level over time.

However such a simple foundation is perfect for a storage shed, playhouse or gazebo.

[youngins]

A skid foundation per the Little House plans and set on a well drained gravel pad will last as long as the building it supports.

1. Can you please confirm these steps to produce an adaquate gravel pad
a. Excavate the building footprint plus an additional foot around the perimter.
b. Depth of excavation should be at least 4".
c. After gravel has been filled and compacted, the pad should be level and at least 1" above ground.

2. What is the best type of gravel to use?

Thanks

[John Raabe]

Best would be clean crushed rock about 5/8" or perhaps larger. You don't want stream bed gravel as the pebbles will roll around rather than lock tight for a bearing surface. The rest sounds fine. Let the bearing soil be your guide. You will need more than 4" if the soil is organic or wet.

[youngins]

HHmmm - North Texas clay ... not very organic or wet, I presume.

Thanks...

Chris