Deck on allotment

[SusSten]

Hello everyone knowledgeable! I want to build a deck of 2x3m on an allotment garden. You are not allowed to add gravel or sand and must avoid posts. Thinking about a "floating" deck that should be as low as possible, do not want "ready-made decking tiles." Tips on dimensions and good advice for laying joists on concrete slabs. From what I understand, it is not appropriate to bury 2 support beams 45x145 NTR A, is that correct? Maybe dumb questions but I've never built a deck with these conditions before.

 

[Henningelvis]

I hadn't buried the joists, but if you have concrete slabs you can lay them on the ground and then use terrace feet to raise the joists a bit and level them.

An example: https://www.biltema.se/bygg/byggbeslag/stolpskor/terrassfot-m-35-65-cm-2000036566

 

[SusSten]

I wouldn't have buried the joists, but if you have concrete slabs you can place them on the ground and then use terrace supports to raise the joists a bit and level them.

An example: [link]

Yes, that's an option I've considered.

 

[Henningelvis]

I imagine that you don't have separate support beams under the joists, but instead place 6 pieces of 45x145 on deck pedestals and lay the decking directly on them. That way, the deck won't be so high. You may possibly need to add blocking between the joists, but if the requirement is for the deck to be as low as possible, then I think that's the best option.

 

[SusSten]

I imagine that instead of having separate support beams under the joists, you would place 6 pieces of 45x145 on terrace feet and lay the decking directly on them. This way, the deck won't be too high. You might need to add blocking between the joists, but if the requirement is for the deck to be as low as possible, I think this is the best option.

I have seen others build decks on horizontal joists to keep it as low as possible, placed closely together and resting on slabs. The reason is that there are quite a few small animals like mice and rats in allotment gardens. Is it an alternative to lay decking on horizontal joists?

 

[Ossian K Olsson]

Hello all experts! I want to build a deck of 2x3m on an allotment. You are not allowed to add either gravel or sand and should avoid post foundations. Considering a "floating" deck that should be as low as possible, I don't want "ready-made decking tiles". Tips on dimensions and good advice on laying joists on concrete slabs. As I understand it, it is not suitable to bury 2 support beams 45x145 NTR A, is that correct? Maybe dumb questions but I have never built a deck with these conditions before.

What will be under where you want the deck? How level is it there today?

 

[SusSten]

What will be underneath where you want to have the deck? How flat is it there today?

It is packed topsoil that hasn't been cultivated for several years, additionally very flat. I was thinking of laying ground cloth underneath.

 

[Ossian K Olsson]

It is packed topsoil that hasn't been cultivated for several years, and it's very flat. I was thinking of laying landscape fabric underneath.

Okay!

Given those conditions, I would use 45x70 as joists and 120x28 decking. Screw everything together and place it directly on the ground. Possibly nail some tar paper under the joists to reduce the strong absorption from the ground.

Since it is pressure-treated, it will still last at least 10 years lying directly on the ground, and since it's floatable, you can also fold it up in the winter and wash underneath if needed.

Not an ideal solution, but the materials cost you 1300 SEK, so you can "afford" to build a new one when the old becomes too unsightly.

Edit: the materials
https://www.bauhaus.se/trall-vida-28x120x3000mm-tryckimpregnerad

https://www.bauhaus.se/regel-vida-4...15779&indexName=nordic_production_sv_products

https://www.bauhaus.se/grundisoleringspapp-yep-2500-0-125x15m

Plus optional decking screws

 

[SusSten]

Okay!

With those conditions, I would have used 45x70 as studs and 120x28 decking. Screwed everything together and placed it directly on the ground. Possibly nail tar paper under the studs to reduce the strongest absorption from the ground.

Since it is pressure-treated, it will last at least 10 years lying directly on the ground, and since it's floating, you can also fold it up in the winter and wash underneath if needed.

Not an ultimate solution, but the material costs you 1300 kr so you can "afford" to build a new one when the old one becomes too unsightly.

That's kind of how I'm thinking too. It feels a bit overbuilt to use 45x145 studs for a small patio on an allotment, and for 10 years, 1300 kr is a reasonable cost. Do you think the 45x70 studs of NTR AB will last that long?

 

[Ossian K Olsson]

That's kind of how I'm thinking too. It feels a bit overdimensioned to build with 45x145 beams when it's about a small patio on an allotment, and for 10 years, 1300kr is a reasonable cost. Do you think the 45x70 beams of NTR AB will last that long?

With the little experience I have, I think you have two choices. One is what I described above to build something freestanding. The second option is to do it properly with ground screws or concrete foundations and proper beams.

Anything in between will both settle and wobble no matter how you do it. Therefore, I think option 1 is perfectly okay!

 

[SusSten]

With the limited experience I have, I believe you have two options. One is what I described above, to build something freestanding. Option two is to do it properly with ground screws or concrete foundations and real joists.

Anything in between will both settle and wobble no matter what you do. Therefore, I think option 1 is perfectly fine!

I will go with option 1, that model suits me best. Thanks for the advice and tips!