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cregan529
Shed foundation options

I need to tear down my old shed which was built on bare soil and is rotting away. I have a 12x8 plan and layup that I like but can't decide whether to build on skids or pour concrete footings. Seems like 4 inches of compacted gravel then some 6x6 pressure treated skids would suffice, but some people I've talked to are against it.

Looking for some insight.

dj1
Re: Shed foundation options

For a long lasting floor, choose a slab, with anchor bolts.

HoustonRemodeler
Re: Shed foundation options

You don't want anything that will trap moisture under wood. Either a slab or put the shed on piers. When placed on the ground, even if over compacted gravel, the transpiration will still collect under the wood and rot out the bottom. Granted it may be a little slower than a dirt foundation, but will rot none the less. My house is on piers, been here since 1920. We know slabs work too.

canuk
Re: Shed foundation options
cregan529 wrote:

I need to tear down my old shed which was built on bare soil and is rotting away. I have a 12x8 plan and layup that I like but can't decide whether to build on skids or pour concrete footings. Seems like 4 inches of compacted gravel then some 6x6 pressure treated skids would suffice, but some people I've talked to are against it.

Looking for some insight.

Yep --- the pressure treated skids will work ---- or --- simply put concrete blocks on compacted gravel --- build the floor frame with pressure treated joists resting on the blocks --- either way will work fine without having to pour concrete piers or a pad.

A. Spruce
Re: Shed foundation options

It bares mentioning that sheds are considered temporary structures which do not require permits. Temporary structures do not have permanent foundations, meaning no slab. That is not to say that you can't put a shed on a slab, but when you do you may be required to get it permitted and inspected.

Having said that, the most common practice is cement blocks to elevate the shed and pressure treated skids. As has been said, you want good air flow under the shed as this will help to minimize moisture/rot issues as well as discourage rats and other critters from nesting under it.

dj1
Re: Shed foundation options
cregan529 wrote:

I need to tear down my old shed which was built on bare soil and is rotting away. I have a 12x8 plan and layup that I like but can't decide whether to build on skids or pour concrete footings. Seems like 4 inches of compacted gravel then some 6x6 pressure treated skids would suffice, but some people I've talked to are against it.

Looking for some insight.

Cregan,

As you can see, we disagree. Actually, your choice has to depend on other factors that we don't know and can't guess:

1. The location and grade of the intended shed, flat or hilly?
2. Soil type and drainage.
3. Your budget.
...and others.

keith3267
Re: Shed foundation options

I have a commercially built 12x16' shed on 6x6 skids sitting on wet clay soil. Had it since 1997 and so far, so good. Everything rots eventually though.

There are concrete supports for sheds and decks sold at Home Depot and Lowes. They are about a foot tall, kind of pyramid shaped with a 4x4 2" deep hole in the center of the top and 2" wide groves shaped in an + pattern. You can put 2x stock in the grooves or short 4x4 posts in the center to support the shed.

canuk
Re: Shed foundation options
A. Spruce wrote:

It bares mentioning that sheds are considered temporary structures which do not require permits. Temporary structures do not have permanent foundations, meaning no slab. That is not to say that you can't put a shed on a slab, but when you do you may be required to get it permitted and inspected.

Having said that, the most common practice is cement blocks to elevate the shed and pressure treated skids. As has been said, you want good air flow under the shed as this will help to minimize moisture/rot issues as well as discourage rats and other critters from nesting under it.

Very good point and was indeed worth mentioning.:cool:

dj1
Re: Shed foundation options

Regarding the permit issue:

You have to check with your local building department.

I once built a 10x12 shed on wood deck in NEW JERSEY, I needed a permit and the shed had to be at least 10 ft from the property line.

A. Spruce
Re: Shed foundation options

I should probably clarify that a little bit.

Temporary structures do not have permanent foundations, hence no permits necessary. There is usually a size restriction as well, usually based on roof square footage of 100 to 120 square feet.

If you pour a slab, the structure will be classified as a permanent structure and as such will require permits in most jurisdictions. If you add electrical or plumbing you'll definitely need a permit.

I should also note that most jurisdictions have set-back requirements. Set-back refers to the distance that you must keep a structure from surrounding property lines. This varies depending on municipality, but generally is 5', though can be as little as 3'. While these figures may seem like a lot, once the shed is in place and you need to get around it to service a fence or do repairs to the shed, you'll quickly find that space to be very narrow and cramped to work in.

Cougars1996
Re: Shed foundation options

From my perspective, the slab is a much better idea, EXCEPT for the tax implications.

If the shed is deemed a permanent structure or improvement, it could very well generate an increase in property taxes. In a place like NY, that increase could eclipse the cost of the shed in just a few years. In such cases, it is sometimes better to do the best, gravel, plastic (moisture barrier) and block foundation you can.

Where I live, in upstate NY, it would be far cheaper to not have a concrete foundation and replace it every 10-12 years than deal with the tax consequences. In some places, like Long Island, you could replace every 5 years and it would be cheaper than the tax increases.

Good luck!!

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