I am sketching a new porch (aka spiketält) for my caravan.
The idea is to build the porch in sections to facilitate transport and summer storage.
I am working on sketches and have now reached the floor (I started ten minutes ago
)
What I want to do is a box 2400x3600mm made of 45x80mm timber with a 4mm plywood on the underside and a 10 or 12 mm on the top side. This box will be filled with some form of Styrofoam/cellular plastic. I want to glue it fully and hope to get a construction that can be walked on.
The floor will be supported by four support legs similar to those under caravans. These will be placed in each corner, recessed approximately 20-30 cm.
The stress on the glue joint and cellular plastic will therefore be quite large in the middle of the floor.
What glue and type of cellular plastic should I use?
The idea is to build the porch in sections to facilitate transport and summer storage.
I am working on sketches and have now reached the floor (I started ten minutes ago
)What I want to do is a box 2400x3600mm made of 45x80mm timber with a 4mm plywood on the underside and a 10 or 12 mm on the top side. This box will be filled with some form of Styrofoam/cellular plastic. I want to glue it fully and hope to get a construction that can be walked on.
The floor will be supported by four support legs similar to those under caravans. These will be placed in each corner, recessed approximately 20-30 cm.
The stress on the glue joint and cellular plastic will therefore be quite large in the middle of the floor.
What glue and type of cellular plastic should I use?
Forget it with those dimensions, you'll flatten it to ground level before the middle and 4 mm plywood can be punctured with a sharp heel.
Kent
Kent
How much sway can you tolerate? The box construction will surely hold if braced internally, but regardless of the construction, there will be sway if 3-4 people stand/sit. Instead, it might be better to construct an underlying frame of pressure-treated wood that is mounted with carriage bolts in suitably sized sections, and on which your floor can rest. Probably sufficient with 145*45 in three rows, and 6 legs, as well as some cross braces.
I can accept quite a bit of sway. The main thing is that the glue/cellplast holds and doesn't crack.
Since it will only be used as a "vestibule" for the caravan, there will rarely be more than one person in it at the same time. It should simply just be a place for dressing/undressing and drying wet clothes.
The goal is to build as light a structure as possible. Preferably, the total weight should not exceed 5-600 kg. Therefore, I want to avoid beams as much as possible.
Since it will only be used as a "vestibule" for the caravan, there will rarely be more than one person in it at the same time. It should simply just be a place for dressing/undressing and drying wet clothes.
The goal is to build as light a structure as possible. Preferably, the total weight should not exceed 5-600 kg. Therefore, I want to avoid beams as much as possible.
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Do as you plan, but at least place an extra leg in the middle. It will still be shaky, but with only legs in the corners, it won't work; it will be like a trampoline.vojma said:
Regarding the weight, I'm pretty sure you'll come well below 5-600 kg without any problem.
A 12mm plywood weighs just under 18kg. You need 3 of those, which is 54 kg. Then the plywood on the underside weighs about one-third of that, which is 18 kg.
Foam is almost negligible, but let's say 5 kg. The beams, well, it depends on how many you plan to use, but to estimate high, say you use 50 linear meters of 45x70 beams, that's about 75 kg.
So you end up at around 150 kg total. If I were you, I would make something much more sturdy, pressure-treated beams, with foam in between, forget the plywood on the underside, it will just mold and deteriorate.
Thank you for your encouraging words vectrex. The thing is, it also needs to be four walls and a roof... and a door... and a window...
Anyone who can offer any good tips regarding which glue to use for which foam boards to ensure good support in the construction?
Anyone who can offer any good tips regarding which glue to use for which foam boards to ensure good support in the construction?
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Build it like some lightweight beams, i.e., plywood on its edge and increased height in the middle. PU glue works but is a nightmare to get pressure on such large surfaces that we're talking about, and since the styrofoam must stabilize the plywood, it's not entirely easy to achieve.
/Kent
/Kent
Currently testing a glue from Casco. It's a floor mat adhesive.
Yesterday morning, I glued a few test pieces and by evening I could confirm that the adhesion is good. Now I've placed the pieces out so they will be exposed to moisture, and we'll see if the glue holds up after that.
I don't remember what the glue is called, but it cost about 150 SEK for a one-liter can. It's also available in 5-liter for about 500 SEK.
Yesterday morning, I glued a few test pieces and by evening I could confirm that the adhesion is good. Now I've placed the pieces out so they will be exposed to moisture, and we'll see if the glue holds up after that.
I don't remember what the glue is called, but it cost about 150 SEK for a one-liter can. It's also available in 5-liter for about 500 SEK.
Sounds promising.
It would be fun if you would like to share your thoughts on the assembly. How were you planning to anchor the wall elements to the floor, corners, and ceiling? You have a bit of a head start since I just started thinking about this today...
Before I saw your post, I was considering custom-made lightweight studs in the floor assembled into a box like yours. I haven't decided on the thickness of the plywood for the "floor" yet. Wall sections with an outer frame and around the window. OSB or thinner plywood on the inside. For insulation, I was thinking of using cellplastskivor, but I haven't found anything in the 70mm dimension, which I think would be optimal. 50mm might suffice, but it complicates the framing a bit.
The roof considerations haven't progressed much yet.
We'll see if I can put together a sketch soon.
It would be fun if you would like to share your thoughts on the assembly. How were you planning to anchor the wall elements to the floor, corners, and ceiling? You have a bit of a head start since I just started thinking about this today...
Before I saw your post, I was considering custom-made lightweight studs in the floor assembled into a box like yours. I haven't decided on the thickness of the plywood for the "floor" yet. Wall sections with an outer frame and around the window. OSB or thinner plywood on the inside. For insulation, I was thinking of using cellplastskivor, but I haven't found anything in the 70mm dimension, which I think would be optimal. 50mm might suffice, but it complicates the framing a bit.
The roof considerations haven't progressed much yet.
We'll see if I can put together a sketch soon.
How did the project go?
It went quite well, but it was significantly more work than I anticipated, and the costs somewhat spiraled out of control.
I had problems getting it sealed at the floor/wall/ceiling connections, so the functionality wasn't quite as good as I had imagined. Additionally, I had envisioned that it would be possible to pack it into small flat packages, but on each element, there is always something protruding, requiring the use of polystyrene or similar during transport/storage, which then takes up more space.
The forecourt was used in the winter of 12/13 but was sold during the fall. I almost recovered the material cost, but considering the amount of work, it was definitely not worth the effort. From now on, I will resort to more conventional building methods.
I had problems getting it sealed at the floor/wall/ceiling connections, so the functionality wasn't quite as good as I had imagined. Additionally, I had envisioned that it would be possible to pack it into small flat packages, but on each element, there is always something protruding, requiring the use of polystyrene or similar during transport/storage, which then takes up more space.
The forecourt was used in the winter of 12/13 but was sold during the fall. I almost recovered the material cost, but considering the amount of work, it was definitely not worth the effort. From now on, I will resort to more conventional building methods.