0

enter image description hereI'm currently trying to build a modern chaise with only two legs.

enter image description hereI will attach a link to it below.

Steps I have done:

Plywood 3/4" cut them into dimensions of the chaise and created a frame and attached it to 3/4" board.

Once that's done got four 14.5" rounds and attached them with 2x4s for the required height.

Attached parallel 3/4" plywood to both legs and attached it to the frame.

Now the issue happens to be when I sit on one end the legs are tilting a bit which tells me it's pulling the other end. But since I'm new to this I need any help you can provide.

https://www.westelm.com/products/mp-fluted-base-chaise-73-h11541/?catalogId=71&sku=6987794&cm_ven=PLA&cm_cat=Google&cm_pla=Furniture%20%3E%20Benches&region_id=668460&cm_ite=6987794_14465514686&gclid=CjwKCAjwvJyjBhApEiwAWz2nLVnU7yx-1wSQKVfKmNws_-8-yYNVjzr1UBBZBbCJ0Ix9Ub32Mf5jpxoCh3EQAvD_BwE

14
  • 1
    I think we need to see what you've built to stand any chance of giving good advice here because without photos we're just guessing what the issue might be.
    – Graphus
    May 20, 2023 at 6:29
  • 1
    @Graphus I have attached the image of what I have built so far above right now. Please take a look and let me know if you need more May 20, 2023 at 15:21
  • 1
    So just to be clear: is it the legs that are wobbling? Or is it that the legs don’t move but the structure feels unstable? May 20, 2023 at 18:54
  • 1
    I'm not going to add a separate Answer as both of the existing ones are good and give some excellent guidance on how you can beef up your version. I do want to specifically emphasise two of the points though — first and foremost, the attachment of the legs to those thin rials that run along the long axis is inherently a bad idea, and second, the top itself probably not being stiff enough. I support the idea of adding a second skin and turning the top into a torsion box; the second skin doesn't need to be as thick as the OSB. [contd]
    – Graphus
    May 22, 2023 at 3:41
  • 1
    The new points I want to mention are in relation to the legs themselves, details that nobody else seems to have noticed. A) the lack of visible fasteners on the bottom surfaces and B) the screw that missed its 2x4 on the left leg. A) how are the bottom rounds attached to the 2x4s given we see no screws?? These should be attached very securely, and screwing through is the best way to do it (add glue as well by all means, but don't rely on it alone). B) if that screw that missed is the same as the rest attaching the top rounds to the 2x4s then I don't think it's nearly long enough. [contd]
    – Graphus
    May 22, 2023 at 3:53

3 Answers 3

3

There's a few things going on that will make this feel less stable.

First, and I'm not 100% sure about this, so possibly ignore, but it looks like in copying the design, you've stretched the main deck wider than 30" and shrunk the diameter of the feet fractionally. This won't be a huge deal, but everything counts.

Second, the deck looks like 1/2" OSB, and the combination of 1x2, 1x3, and 1x4 (we'll call all that the "subframe", for lack of a better term) probably isn't sufficient to make that into a stiff surface. It can help to drive a bunch of 1-1/4" screws from the top side through the subframe. The 1x4 that turns into a 1x3 on the right side of the picture isn't helping as much as it should -- a continuous piece of wood would be much better. To stiffen this surface, add more wood, with screws from the top side of the OSB. To really stiffen this surface, make a torsion box with another layer of OSB on the bottom.

Third, and the biggest issue, is that you've stacked flimsy 1x2 rails on top of different subframe members. It's not clear how these are attached (except for a couple of visible t-nuts), but you need to pack the empty space between the legs and the top with solid wood. That means a 1x6 (or bigger, if it'll fit) between the main subframe and the two 1x2 rails, and 3 strips (as wide as possible) between the subframe and the feet. The end goal is that the tops of the feet have wood between them and the OSB top. Now attach from the top side of the OSB through the padding, into the tops of the feet with plenty of 3" screws. Predrill clearance holes in the OSB and the 2 layers of packing, and pilot holes in the foot.

Parenthetically, it's not clear to me why you opted to add those 1x2 rails that run sideways. If they're needed for stiffness along the 6' axis, put them out at the edges. (Better yet, put them on edge around 4 sides like a table apron, as opposed to on the flat.) As they're placed, they're not really helping and will cause upholstery trouble later on.

1
  • 1
    Thanks for the answer. The reason i attached the 1*2 perpendicular to the flame was i read somewhere that it provides support by attaching two legs together with some wood, Instead of leaving them seperate. But i dont think it added a lot of support. So like you suggested i might remove them and put them on the ends May 22, 2023 at 20:52
3

The design and construction is inherently unstable.

You would do better to remove the 1x material and build the platform with two or three layers of plywood laminated together using glue and screws. That should remove any flex in the surface as weight is applied to the chair.

Attach the pedestals directly to the platform surface with four or more fasteners each. The flat surfaces of the platform and the tops of the pedestals fastened together should prevent (or greatly mitigate) the platform shifting on the pedestals.

You might encircle the platform with solid wood (maybe 1x3 or even 2x3) to hide the edges and for some added rigidity for the platform.

After taking the steps above to improve the stability of the construction, there remains a possibility that the entire structure, as designed, would be prone to tipping if someone sat on the extreme edges or the corners. This concern extends to the original design as well. The chair may need larger diameter pedestals to be entirely stable.

Furniture needs to be designed and built to account for the "odd" things people subject it to. For example, will this support three or four people along the edge? What if the people are engaged in activity more dynamic than just sleeping or sitting on it? What if someone sits on the end or corner? What if two people sit on an end?

5
  • If I might suggest, the point about the possible weaknesses in the original could do with being emphasised, even if just to italicise or make bold the "This concern..." sentence. I heartily agree and it may be the key thing here that wasn't obvious from the outset.
    – Graphus
    May 22, 2023 at 3:18
  • Two things re. your point about OSB and exterior application. I don't see anywhere else a reference to this being exterior furniture, is that mentioned in the original link that I can't view? And about OSB, over here at least it's commonly very moisture resistant. Resistant enough that it is sometimes used in preference to exterior plywood. Seeing its use externally at a few building sites swayed me in favour of using it to make my last cat house, and as far I can tell that's still sturdy after three years in the weather.
    – Graphus
    May 22, 2023 at 3:30
  • @Graphus - Good points. I don't recall explicitly seeing that the original is marketed as exterior furniture. For whatever reason, I see the word "chaise" and immediately think "patio furniture". As far as moisture problems with OSB, I suppose you may be right... or more right than I am. OSB is used extensively in framing/construction and it seems to handle being rained on, etc, but I have a garden shed made of the stuff...not a huge fan based on how it's been holding up over the years.
    – gnicko
    May 22, 2023 at 15:27
  • Yeah OSB is going to vary for sure, just like the plywood it attempts to supplant!
    – Graphus
    May 22, 2023 at 15:39
  • Yes this is for interior only. But like you said the weight i want it to hold is atleast 200lbs so if you have any other suggestions on supporting that weight that would be helpful. May 22, 2023 at 20:56
1

Now the issue happens to be when I sit on one end the legs are tilting a bit which tells me it's pulling the other end.

How much does your version weigh? The one from West Elm says that it weighs 154 lbs, which seems like quite a lot for a simple platform with cushion. It's a good bet that those two pedestals are weighted with something, and that all that weight improves the stability of the piece.

You can do the same thing, but it'll be easier if you change the pedestals so that the 2x4's are each turned 90° and there's plenty of open space in the center. There are lots of inexpensive materials you can use to add weight. 50 lb bags of play sand cost around $7 each near me, and 80 lb bags of concrete mix cost even less. Adding water to the mix will give you an even heavier product at no added cost, but of course it's a little more work. With the supports turned, it looks like a 5 gal bucket would fit in the middle of each pedestal, so a bucket might make a useful form.

1
  • 1
    Wowza, a buck fifty? There's a detail I wouldn't have expected!
    – Graphus
    May 23, 2023 at 4:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.