Author Topic: Foundation for my "she shed"  (Read 1556 times)

mozar

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Foundation for my "she shed"
« on: July 08, 2020, 10:04:09 AM »
I am looking to tear down my current shed. It's very unpleasant and starting to rot at the bottom. It's so hot in there it's hard to get the mower out. Also plants are able to grow into it.
I live in the mid-Atlantic area (for frost line purposes). I'm thinking I could put a 8X16 shed there (currently 8X8). I would like it to serve as a guest house in the spring and fall months. I will probably build it myself.

I am not allowed to put in a concrete slab.

So, that leaves me with a gravel pad (truegrid pro), wood or metal piers, cement blocks or wood planks.
I like the idea of a gravel pad but I'm not sure how I would secure the shed to the ground. Would this be an issue? Any tips?

GoCubsGo

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Re: Foundation for my "she shed"
« Reply #1 on: July 08, 2020, 10:44:51 AM »
You aren't allowed a concrete slab but can run utilities to it and make it into a guest house?  I've built sheds on pressure treated platforms that have held up well (with gravel underneath).  Not sure I'd want a full conditioned space without a slab though.   Make sure to find out if it needs to be move-able per code and if there are any lot line restrictions/size restrictions.  My town is super strict on sheds and want permits for everything.  All it takes is one neighbor to call you in. I've seen it happen twice. 

mozar

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Re: Foundation for my "she shed"
« Reply #2 on: July 08, 2020, 10:53:31 AM »
I won't be running utilities. I'm thinking a compostable toilet and a small solar panel.

It doesn't need to be move-able and there are lot line restrictions. Not sure about size yet. My HOA is very strict and will require a building permit.

Quote
I've built sheds on pressure treated platforms that have held up well (with gravel underneath)
Is this different from plywood on top of 2x4s?

Fishindude

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Re: Foundation for my "she shed"
« Reply #3 on: July 08, 2020, 11:04:01 AM »
If you are not running utility pipes and wires to it, it does not matter if it moves around slightly with freeze thaw conditions, as there are no pipes to break.
I'd just level and compact a nice gravel area to keep things clean and prevent weed growth, frame a floor system out of treated lumber, then set the framework on precast concrete blocks or pavers.
If you're concerned about wind moving it, use a few hurricane tie down straps like they use on house trailers.   There are a whole lot of garden sheds out there that have nothing holding them down but their own weight.

P.S.   I've not heard many positive things about composting toilets.

« Last Edit: July 10, 2020, 07:15:05 AM by Fishindude »

SunnyDays

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Re: Foundation for my "she shed"
« Reply #4 on: July 08, 2020, 11:04:38 AM »
I replaced my plywood shed floor with cement patio blocks a few years ago and couldn't be happier.  The plywood was rotting due to the shed being in the lowest part of the yard and all the snow melt accumulating under it.  The bottom boards were also rotting and had to be replaced.  The floor sits inside of the shed frame though, not beneath it.  I did find that there was a lot more pooling of water in the spring once the water didn't have the floor to go under, so I had to dig a trench to let it flow out.  Small sacrifice though.  The shed is much cooler inside now with the blocks.

freeat57

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Re: Foundation for my "she shed"
« Reply #5 on: July 08, 2020, 11:05:48 AM »
When I lived in the Midwest, I built a 3-season greenhouse (emptied in Summer).  It was specifically designed for orchids and other tropicals.  The north wall was solid without windows and insulated.  the other walls were solid and insulated to bench height and glazed above.  So, it was a pretty substantial structure compared to many greenhouses.  Size was 8'x12'. The foundation was made by digging out a level rectangle about 3"-4" deep, tamping down and filling with pea gravel.  Then 6"x6" treated wood beams were squared on the gravel and fastened together. The walls were built as modular units, then placed on the foundation beams and bolted down. I used it for 16 years until I moved. Even in wind storms that took down trees all over the neighborhood, that sucker never moved a millimeter, even though it was "just sitting on the ground".  You can make a floor inside with patio pavers.  It had gas heat and electricity.  In my city, codes allowed a shed up to 10'x12' with no permit required as long as there was not a permanent foundation and no plumbing (water).  Be sure to check the regs for your city.

GoCubsGo

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Re: Foundation for my "she shed"
« Reply #6 on: July 08, 2020, 11:11:03 AM »
I would basically build a 2x6 pressure treated "deck" and put 3/4" marine plywood over that if you want to build it to last a long time. Make sure the siding is pretty sturdy and maintenance free (cement board or vinyl) as most sheds that fall apart is because people don't have the time/inclination to maintain them (paint and caulk).  I couldn't sink posts per code so I used pre-cast concrete post holder set on a tamped down gravel and stone foundation.  Hasn't moved in 12 years.

I would never build a shed that big with 2x4's.  Your going to build a fairly large structure.  If you do it right it will be an asset.  If you cheap out it will be a liability in 10 years.

Laura33

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Re: Foundation for my "she shed"
« Reply #7 on: July 08, 2020, 12:22:46 PM »
I don't understand why you would be allowed to build an ancillary structure equipped for people to live/stay in short-term, yet would not be allowed to install a concrete pad.  Is this an attempt to get around HOA/building code restrictions, i.e., no concrete pads allowed because they are trying to prohibit permanent backyard structures other than unoccupied/temporary storage sheds?  If so, I'd be pretty careful about putting money into something like that given the possible trouble down the line if the HOA gets wind of how you're using it. 

mozar

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Re: Foundation for my "she shed"
« Reply #8 on: July 08, 2020, 01:13:24 PM »
The HOA is pretty chill as long as code as followed.
A previous owner of my house wanted to put in a concrete slab with a fence around it for his dogs. The HOA wouldn't let him do it so he moved. I think its more about water drainage.

My county says that I can have a shed without a permit as long as it's under 150ft. The county allows a concrete slab but my HOA does not as far as I know. I'm not going to be renting it out but I will look into accessory dwelling units.

Thanks for the suggestions.

trollwithamustache

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Re: Foundation for my "she shed"
« Reply #9 on: July 09, 2020, 01:54:05 PM »
I've got the gravel with enough height/slope (tiny bit) that the metal base beams of the shed drain to dry after rain. It seems to work good enough, but this is Cali so our weather stress is pretty mild. I think if I had put the shed in (it was here when we got the place) I'd use some kind of concrete block to elevate the base beams a little.

You can get mobile home hurricane straps that should be more than enough tie down strength. I bet there are similar products for sheds. For something little like this, you can definitely put a helical anchor in yourself if desired.

BTDretire

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Re: Foundation for my "she shed"
« Reply #10 on: July 11, 2020, 12:58:29 AM »
I built a 12 x 16 she shed about 18 months ago. I laid 3 or 4 patio blocks level on the ground, then made two 16ft beams be screwing 2x6s or 2x8s together that I laid on top of the blocks. I did use the mobile home hurricane straps with helical anchors to hold the double 2x6 (or 8") beams down. Then I built the floor framing on top ot the beams. I think I notched the beams for the floor joists.
 With this arangement nothing except the patio blocks touch the ground, so nothing to rot.
 I think I might have some pictures, but they are on a different harddrive. I can check tomorrow to see if I have any useful pictures.
 Start drawing the plan asap, so you can go over it and find mistakes. Remember sheet plywood is 4ft, so if you use 1/2in plywood the outside dimensions of your floor frame needs to be 15ft-11inches x 12ft, if the 12ft side overlaps by 1/2in at each corner.
 It's sad how few details I can remember, I do recall I ordered the anchor kit from Lowes, (made a $1500 order for the she shed) but it didn't come in when I needed it, so I had to buy all the anchor items separately at higher cost. That's probably why I remember that!

BTDretire

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Re: Foundation for my "she shed"
« Reply #11 on: July 11, 2020, 06:52:37 AM »
I found some pictures.
 I installed 4 anchors.

Rosy

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Re: Foundation for my "she shed"
« Reply #12 on: July 11, 2020, 07:02:08 AM »
I built a 12 x 16 she shed about 18 months ago. I laid 3 or 4 patio blocks level on the ground, then made two 16ft beams be screwing 2x6s or 2x8s together that I laid on top of the blocks. I did use the mobile home hurricane straps with helical anchors to hold the double 2x6 (or 8") beams down. Then I built the floor framing on top ot the beams. I think I notched the beams for the floor joists.
 With this arangement nothing except the patio blocks touch the ground, so nothing to rot.


We bought a custom she-shed, extra windows 16X14 at a local company. We had another company come in and level and tamp down the ground. When the shed was delivered one guy built the whole thing in two days.
Set up on what to me looked like stepping stones but they assured me those were manufactured to hold considerably more weight than a regular paver. He doubled stacked them and used maybe 80 pavers or so overall.

They used hurricane cables as our code requires - it is suitable for living in, has AC/Heat and a separate electric box, we insulated it and drywalled it too. Except we never had it plumbed due to costs - we have had friends and family stay and sleepover, but I do wish we had gone ahead with water and plumbing for a toilet and a shower/sink.
The building material is guaranteed not to rot. So far we haven't had any issues - ten plus years in - except with the shingles (3 times and they came to fix it 3 times twice under their guaranty and the last time out of courtesy - no charge) haven't had any problems since.

In retrospect - if you spent the money on a decent shed - go the extra mile and make it multi-functional for what you really want to use it for.
I've been thinking I may place an outdoor shower there - it would be great to be able to take quick shower after gardening in this heat and could be functional for anyone staying in the shed too.
A  rather cheap project/option for our climate.

For us it has been a lifesaver - it serves so many different functions, money well spent. I took pics of the built they may still be on the hard drive if you want to see - I'll try to find them.