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Window bench: Pocket hole vs more crude method

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Forum topic by GabeATX posted 07-22-2016 12:57 PM 913 views 0 times favorited 6 replies Add to Favorites Watch
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GabeATX

5 posts in 140 days


07-22-2016 12:57 PM

Topic tags/keywords: question pine joining

I am building a 57” wide 24” deep bench in a nook in my bedroom. I plan on screwing 2×4 horizontal supports into the back and side walls of the nook with 4” screws, to form the main support for the bench. I will make 3 horizontal 2×4 supports running the width of the bench, and have a dilemma:

Should I join these supports to the wall-mounted 2×4 supports using pocket holes (Kreg jig). Never tried this.

Or

What about just arranging my horizontal supports on top of my wall-mounted 2×4’s? They could be set vertically, and I could glue little 2×4 spacers between them to keep them in place. Imagine one 2×4 against the wall and another on top of it, perpendicular, both arranged vertically.

The latter seems like a more bulletproof design. No need to do pocket holes and in my head it seems stronger. Just wondering if I’m missing something obvious.

Also wondering if I need another vertical support in the middle (from the floor) given the width and depth.

Thanks in advance, this is my first project like this and want to make it solid.


6 replies so far

View JBrow's profile

JBrow

819 posts in 387 days


#1 posted 07-25-2016 03:14 AM

GabeATX,

A sketch would have been helpful, but I think I understand your project and questions. My understanding is the 3 horizontal 2×4s will support what I presume to be ¾” thick plywood seat. The pocket hole method would have the horizontal planks butted up to the wall cleats and the tops flush. Pocket screws would hold the horizontal planks in place. In the second method, the wall cleats are set 3-1/2” lower than in the pocket screw method and the horizontal 2×4s set on edge atop the wall cleats.

Either method would probably work, but since the time may come when two or more people may be seated at the window, I would tend toward the second option. The pocket screw method would require fairly exactly cut lengths of the horizontal members to minimize any gaps at the ends of the horizontal members. A good friction fit of each horizontal member would, I think, be best for pocket screws. The strength of the seat support structure would rely on the strength of the pocket screws and the wood surrounding the holes drilled in the horizontal members. I assume the horizontal members would be oriented with the edges of the horizontal members up and down (similar to floor joist orientation).

The alternative stacking method eliminates reliance on the strength of the screws and surrounding wood of the pocket screw method. Also cutting the horizontal members to an exact length is not nearly as critical. In-filling the gap between the horizontal members with 2×4s between the horizontal members and setting atop the wall cleats would provide additional support of the plywood seat decking at the edges. This in-filling may or may not be necessary, but I would add the perimeter support to be sure.

A 54” open span seems a little long to me without any center supporting structure. With enough weight on the seat, some sagging could occur. I hate re-visiting a project I thought I had finished to make repairs. Although you may get by with just one center support, I would err on the side of too much support rather than perhaps not enough. Were it my project, I would probably support the 54” span every 16”, although every 24” would may be enough.

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rwe2156

2198 posts in 947 days


#2 posted 07-25-2016 03:19 PM

I would not use pocket holes in this applicaton.

I would build the whole frame first nailing it together similar to a stud wall.
Mount preassembled frame to wall rather than building in place.

Definitely needs support. You can’t have it hanging in the air. A leg in the corner is one option.

Another option is two layers of plywood is another for increased stiffness.
Another is make an apron using 2×4 material.

Completely encasing with a base of ply set in a couple inches is another (which I think is best.)
With it, you could incorporate a couple doors and have storage.
You won’t be hitting a let with the vaccuum either ;-)

-- Everything is a prototype thats why its one of a kind!!

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Rick M

7933 posts in 1847 days


#3 posted 07-26-2016 03:53 AM

A 2×4 across the back and both ends is going to give you a lot of support. I’ve built plenty of office desks that way, with 1” thick top and 3/4” edging strip in front and had people stand on them. They sag but don’t break and some of them were 8-10 feet long. So how much support you need depends completely on the material and thickness of the top. 54” is not that long. I have 3/4” shelving in the laundry closet with longer spans than that. I would forget about the extra 2×4 supports and just go with an edging strip in front. Top should be 3/4” minimum with edging strip or 1” without.

You might have fun with this:
http://www.woodbin.com/calcs/sagulator/

-- http://thewoodknack.blogspot.com/

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GabeATX

5 posts in 140 days


#4 posted 07-26-2016 12:25 PM

thanks JBrow and rwe2156 and Rick M. This is great feedback. Back to the drawing board to rework the approach a bit.

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GabeATX

5 posts in 140 days


#5 posted 07-31-2016 10:11 PM

OK, took the advice given here and beefed up the design. It’s actually 67” not 57”, and I am making two 30” boxes to serve as bookshelves down in front, so beefed up vertical supports right behind the bookshelves and in between them. Someone asked for Mary Tyler Moore bookshelves, anyone remember those?

Here’s what it looks like, framed up. It feels solid. something I didn’t count on: this corner of the house dips, so I have to shim the legs.

This will get a 3/4 plywood top. For looks it will get a 1X6 facing along top and bottom and either 1×6 or 1×4 vertical faces. Not sure if I will pick up the baseboard style—the whole room has baseboard plus some rounded extra stuff tacked onto it, kinda odd looking.

I appreciate the advice, folks.

View Rick M's profile

Rick M

7933 posts in 1847 days


#6 posted 08-02-2016 05:22 AM

LOL. Are you putting us on? I bet it feels solid, you could park a car on it.

-- http://thewoodknack.blogspot.com/

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