DuraMax assembly
The shed cannot hold itself up.
A DuraMax frame cannot span open space. It has to be supported continuously, everywhere. So the foundation is not preparation for the shed. The foundation IS the shed’s structure, and almost every problem people have starts there.
Vinyl panels on a thin metal frame, and what that means
DuraMax sheds are rigid PVC wall and roof panels, reinforced by galvanised steel profiles. They do not rust, rot, dent, mildew or need painting, they are quieter in the rain than a steel shed, and owners routinely report them looking new after fifteen or twenty years. As a low-maintenance storage building they are genuinely good.
What they do not have is a structural floor. A reviewer who built one put it exactly: the framework cannot span any open space, so it must be supported continuously everywhere. Lay it on ground that dips, and the shed does not bridge the dip. It follows it, and then the doors stop closing.
Which brings us to the thing that catches nearly everybody, and it is in the product name.
How long, by size
DuraMax’s own figures. Owners broadly agree, once the base is sorted.
| Model | Time | People |
|---|---|---|
| 5x3 YardmateThe small one. | 1 hour | 1 |
| 4x8 SideMateAn owner and his son did one in 3. | 3 to 4 hours | 2 |
| 8x6 DuraMate | 3 to 4 hours | 2 |
| 10x8 WoodBridgeOwners say "a day", and mean it. | 4 to 5 hours | 2 |
| THE FOUNDATIONOwners repeatedly say this is where the day went. | longer than the shed | 1 to 2 |
| DuraMax’s own install serviceThey quote it, and they partner it out. | from $585 | them |
It feels alarmingly flimsy while you are building it and stiffens up dramatically once the roof is on. Owner after owner says this. It is not going wrong.
The foundation, and the four things nobody tells you
The "foundation kit" is not a floor. It is a frame.
Models are sold as "with Foundation", and people reasonably assume that means a floor. It does not. The foundation kit is a galvanised steel frame that lifts the shed about two inches off the ground and keeps it square. You STILL need a flat, level base underneath it, either a concrete pad or a timber frame, and you still need to buy plywood to lay on top of it. DuraMax recommend 3/4 inch exterior grade CDX. It is not in the box.
You measure the interior floor AFTER you build the shed
The best detail an owner has ever handed us. The interior floor sheet has to be precisely trimmed to the inside dimensions, and those dimensions vary slightly depending on how accurately you built the shed. So you cannot pre-cut it. You build the shed, then you measure the inside, then you cut the floor. Anybody who cuts it first is guessing.
The part numbers are stamped in the metal, faintly, and the manual does not say so
This one saves an afternoon. An owner found the paper tags had fallen off his parts inside the box, and this kit has a great many similar-looking pieces. He then discovered the part numbers are faintly STAMPED INTO THE METAL itself, which the instructions never mention. If your labels are gone, look at the metal before you start guessing.
Check the diagonals before you go near the roof
A reviewer found the roof holes would not line up, assumed a manufacturing fault, and then measured the diagonals across the inside of the shed. They were different. The building was out of square, and the roof was simply telling him so. Measure diagonal to diagonal, get them equal, and the roof will fit.
There will be leftover holes in the back, and they let water in
Because the door can be fitted on either side, the panels are pre-punched for both, and you finish assembly with a row of unused holes on the back. An owner filled the small ones with the spare screws and clips from the kit, which supplies extras, plugged the two large ones with spare roof clips, and sealed the lot with clear silicone. He said afterwards you cannot see it. That is ten minutes that stops water getting into the frame for twenty years.
Report damage within 48 hours, with photographs
DuraMax will send free replacements for damaged or missing parts, but their stated window is 48 hours from delivery, with pictures. Open every box and check the contents on day one, not on the weekend you finally get to it.
The base is the job
Get a level concrete pad if you can. If you cannot, build a timber frame from 2x4s or 2x6s with cross-bracing so nothing is unsupported in the middle, and lay 3/4 inch exterior plywood on it. DuraMax include instructions for building the timber version.
Then the kit’s metal foundation frame goes on top of that, and the interior floor goes on top of the frame.
Buy the plywood before delivery day, because the kit does not contain any and you will not want to stop halfway.
Build it somewhere with space around it. It is light enough that two reasonably tall people can carry the finished shed to its final spot by lifting on the roof support brackets from the inside.
Why people hand it over
Because the shed is the easy half and the foundation is the hard half, and the foundation is the half that decides whether the doors ever close properly.
Because a great many owners get to the roof, find the holes do not line up, and conclude the kit is faulty when in fact the building is out of square by half an inch.
And because DuraMax themselves quote installation from around $585, which tells you what they think it is worth.
One thing worth saying plainly: this is a weatherproof storage building, not a strongbox. Owners note that determined thieves could get through the panels. Store the mower in it. Keep the valuables somewhere else.
What an installer does
- Builds a properly level, CONTINUOUSLY SUPPORTED base, which is what the shed actually needs.
- Supplies and cuts the plywood the "foundation kit" does not include.
- Assembles the panels square, checking the diagonals BEFORE the roof goes on.
- Measures and trims the interior floor to the real inside dimensions, after the shed is built.
- Plugs and seals the unused door-side holes so water cannot get into the frame.
- Checks the doors swing and latch properly, which is the real test of whether the base was right.
Get it built by someone who has built one before.
Tell us your ZIP and what you bought. Installers near you will quote you directly, and you deal with them, not with us.
Questions people ask
Does the DuraMax foundation kit include a floor?
No, and this is the most common misunderstanding. The foundation kit is a galvanised steel frame that squares the shed and raises it about two inches. You still need a level base beneath it, concrete or timber, and you still need to buy plywood, ideally 3/4 inch exterior grade, to lay on top of it.
Why does my base have to be perfectly flat?
Because the shed framework cannot span open space. It must be supported continuously along its whole footprint. Unlike a timber shed with joists, a DuraMax has no structural floor of its own, so any dip in the ground becomes a dip in the shed, and then the doors stop closing.
Why will my roof panels not line up?
Almost certainly because the building is out of square rather than because the parts are wrong. Measure the diagonals across the inside of the shed. If they are not equal, the structure is racked. Square it up and the roof will fit.
Can I cut the floor before I build the shed?
You can try, but the interior floor has to be trimmed to the actual inside dimensions, and those vary slightly with how accurately the shed was assembled. Build first, measure second, cut third.
Can I take it down and move it later?
Yes. DuraMax say you can dismantle and rebuild one, but you will need fresh plugs, pins and washers, which they sell. It is one of the genuine advantages of a panelised vinyl shed over a timber one.
Installers.org is not affiliated with, endorsed by, or sponsored by DuraMax or U.S. Polymers Inc. DuraMax is a trademark of its owner, referred to here only to describe the assembly services that independent installers on this directory provide.