Will it wobble... Sun Room Shelf/Bench.

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Forum topic by Hatric posted 12-28-2016 02:29 PM 595 views 0 times favorited 6 replies Add to Favorites Watch
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5 posts in 1380 days

12-28-2016 02:29 PM

Topic tags/keywords: question

So i’m putting together some plans I have in my head for what I would like to do with our back “sunroom/playroom” We have lots of tubs of kid toys but no real good way to store them that would be easily accessible to the kids.

I was hoping for something a bit more elegant at the same time rather than just painted plywood shelves.

Also hoping to utilize the top as a bench so I would expect to have some cushions on the top.

Now on to the project I have some sketchup drawings I did to visualize the project but i’m worried what I have will just wobble with weight and wondering the best way to solidify it. Maybe a thin plywood backing to help strengthen it up, or do I need something else?

I’m just trying to see if this is a valid design before I start making it… I would rather not get to final steps and realize it’s a terrible design.

I can provide the file if you’re interested.

6 replies so far

View JBrow's profile


1366 posts in 1119 days

#1 posted 12-29-2016 07:54 PM


Your design looks pretty good to me, although I offer a few ideas to supplement the current design. Since the surface of the bench will provide seating, I would worry about the seat sagging between vertical supports. A simple rail connecting the vertical supports and let into the a rabbet at the top of the front the legs would be an approach to address this potential issue. The top rail would support the front edge of the seat. The same issue could exist on the wall edge of the seat. I doubt that a rail to support the mid shelf would be necessary unless the mid shelf would carry significant weight.

A piece of plywood as a back would protect the wall from damage. I do not believe the plywood back would be needed to prevent lateral movement of the vertical supports. If the vertical supports are attached to studs in the wall, I doubt lateral movement would be a problem, especially with the shelf attached to the mid rail in the vertical supports.

Careful consideration to the placement of the mid shelf could ensure the space under the bench will provide the type of storage required. If the toys are gathered up and placed in plastic totes or boxes, the mid shelf could prevent the totes or the boxes from sliding under the bench.

With more work, the compartment under the bench could be hidden with some doors, giving the bench a dramatically different look. The doors would also hide the contents under the bench. Since this is a playroom, I do not believe I would enclose the compartment and leave storage access by a hinged seat that lifts up for access. I worry about little fingers getting in the way of a closing lid or seat.

View OSB's profile


147 posts in 725 days

#2 posted 12-29-2016 11:49 PM

If you find a specific bin to fit under the bench, you can add some thin vertical supports between them to reduce the span between support.

Square frames are not great for stiffness because squares and rectangles are parallelograms so the corner joint is the only thing that provides stiffness. In a stick built home, certain walls are sheeted with plywood to create panel stiffness. That has the same effect as a diagonal brace. You will notice that it isn’t done on all walls, usually just enough to create a stiff core to the building that everything else locates on.

If you fasten the bench to the floor and the back wall, they can give you panel stiffness along with the top. If the design is right and you don’t skimp on fasteners it will be solid.

View popztoolz's profile


4 posts in 3241 days

#3 posted 01-02-2017 08:38 PM

Hatric: I agree with a lot of the ideas pointed out by both JBrow and OSB. The spans look too low for seating support without rails for support. If you go with 2” boards instead of 1” you may get away if the weight load is not excessive. From the drawings it looks like it is going to be around 42” span between legs. The dadoes are a good idea but may not be needed, I would recommend using a Kreg jig and using pocket screws to attach everything together. They will help keep it from racking and gives a tighter joint. It looks from your drawing that all the pocket screws would be hidden underneath and for a nicer look they can be filled in. Happy woodworking and best wishes on your project.

View Hatric's profile


5 posts in 1380 days

#4 posted 01-03-2017 03:59 PM

Thanks All of you for the responses they are all very helpful. Sorry for the delayed response – I have been traveling.

JBrow: The spacing is currently setup based on a set of totes we are already using – they just get stacked on the floor or in a corner – sometimes extremely high which is scary with little ones around. I like the idea of a rail to support the top shelf. I wasn’t planing on attaching it straight to the wall though – but that isn’t 100% off the table if it looks like I need the support I can always attach later. The doors would definitely look good – but the totes will likely be too tight of a fit. Trying to get them organized a bit better but also not consume the whole room as there is a book case in here as well and i’m loosing floor real estate fast :-).

OSB: Do you think the additional vertical supports would need to be down to the ground or just between shelves? I’m 210 – and the largest in the house by far I would likely just use a support as my seat considering I pay attention to things like that. I don’t expect a huge amount of weight up top it’s just throw a pillow on it and call it a bench so toys don’t end up being stacked there too. Also the rectangle debacle is why I was worried about it racking so i’m trying to figure out how to best limit that – maybe some angled brackets near the vertical supports?

Popztoolz: I was thinking Dado to take some of the weight – would you say Dado + Pocket Screws? I have the Kregg jig – i’m Wondering if I can get the jig up high enough to compensate for the dado space not sure how to say that. Moving it’s “Edge” out half an inch. Increasing the top bench size is also an option – but if I go with JBrow’s idea of a horizontal support rail from support to support would that minimize the need for a full board increase? Say a 2” rail connecting them with a Rabbet along the top for the bench to rest in – front and back.

So last piece I’m curious about is the corner piece. Do I do a similar horizontal support between the Vertical front/back, but mitered and go corner to corner rather than a straight mortise and tenon like the other vertical supports?

View OSB's profile


147 posts in 725 days

#5 posted 01-03-2017 06:41 PM

The way to make a beam stiff is to make it tall.

Your seat looks too thin for the span to me. If the seat bows down under the weight, it will pull the verticals in with it, that is not good.

If you only connect your vertical support from the top to the shelf and not the floor, you have more rectangles that can hinge down, it would do very little to stiffen the seat. I would make the support go to the floor.

From a design philosophy standpoint, I don’t think making furniture that requires thought for use is a good idea. Eventually someone will sit on it without thinking and you get a broken bench.

View Hatric's profile


5 posts in 1380 days

#6 posted 01-03-2017 06:47 PM

Fair enough that makes sense. I’m sure there will never be a drunken buddy in my house!

So thicken up the bench board to ~2” or/and add additional vertical supports?

Edge to Edge the longest stretch is ~39” the spans closer to the window are ~27”

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