how can I mount 5 ft floating shelves(solid walnut) to concrete wall

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Forum topic by Tunalmelt posted 01-14-2015 06:38 PM 1884 views 0 times favorited 10 replies Add to Favorites Watch
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5 posts in 1131 days

01-14-2015 06:38 PM

Topic tags/keywords: keyhole floating shelves brackets mounting help concrete wall

First post here,

Working on these floating shelves made of black walnut with a live edge.
Shelves will be floating on a concrete wall
they are 10 inches deep 5 ft long and 1.5 inches thick.

Anyone had and success with floating wall brackets?
have any clue what keyhole mounts can hold in terms of weight?

Im open to any and all suggestions

Thank you!


10 replies so far

View bigblockyeti's profile


4981 posts in 1623 days

#1 posted 01-14-2015 06:50 PM

Keyhole mounts (the metal ones mortised into the back) might be able to work, but given the weight of such a piece of lumber, it’s likely you’d need several. Luckily you won’t be hunting for a stud every 16” and you can put them wherever you need. I’d use 2” tapcons every 6” – 8” for good insurance and the largest diameter that would physically fit into the keyhole mount. The screws (especially the top one) that hold the metal plate into the mortise should be substantial as well. Most are designed for minimum tension and maximum shear, this setup would represent the inverse.
Another option would be a 1 1/4” x 1/4” metal bar with steel dowels welded in and protruding from the flat side that could be mortised and drilled into the back of the shelves after being attached to the concrete wall via several tapcon screws. It would be a lot of work, but should offer great support.

View dawsonbob's profile


2733 posts in 1658 days

#2 posted 01-14-2015 06:57 PM

Just out of curiosity, is it solid concrete, or cinder block?

-- Mistakes are what pave the road to perfection

View Tunalmelt's profile


5 posts in 1131 days

#3 posted 01-14-2015 07:17 PM

Im pretty sure its solid concrete. Its for a friends of mine for his apartment in london and he wall seemed to be solid concrete.

View LeTurbo's profile


226 posts in 1488 days

#4 posted 01-14-2015 07:20 PM

I’d be inclined to drill deep into the back of the shelf, so that I could slide it onto some threaded rod which, in turn, is drilled into the concrete with rawlbolts. It depends on what they’re expected to hold – certainly books and the like add huge weight.

View splatman's profile


586 posts in 1302 days

#5 posted 01-15-2015 03:03 AM

Drill 1/2” holes in back of shelf, and matching 1/2” holes in wall, and “dowel” the shelves to the wall with 1/2” steel rods. This will also work for wood-framed walls. Just make sure the holes are centered in the studs. This is really just a heavy-duty dowel joint. Use figure-8 tabletop fasteners to keep the shelves from sliding off the rods. Place the exposed half of the fastener on top, so it will be hidden by the objects that the shelf will hold.
The only question is, how deep into the wall and shelf? Maybe 2” into the wall (concrete) or 3” (wood) and 1/2 the width of the shelf into the shelf?

View Tunalmelt's profile


5 posts in 1131 days

#6 posted 01-15-2015 02:56 PM

My only concern is making the install as easy as possible for him. His knowledge of any of this is to just about use a level and a driver. Thats why I am a bit weary of him drilling holes into the concrete with metal rods.

Would something like this suffice?

View Buckethead's profile


3194 posts in 1771 days

#7 posted 01-15-2015 03:08 PM

Ya… That’s a doable option and a very expensive one too. I’d not go that route since a better, stronger method of embedding a rod into the concrete would be far less money. Not rocket science. Pretty simple and straightforward.

-- Support woodworking hand models. Buy me a sawstop.

View Bluepine38's profile


3379 posts in 2988 days

#8 posted 01-15-2015 05:39 PM

An apartment is normally rented and any holes or rods would have to be removable when they left to
avoid costly repairs.

-- As ever, Gus-the 79 yr young apprentice carpenter

View Tunalmelt's profile


5 posts in 1131 days

#9 posted 01-15-2015 06:09 PM

once a hole is drilled into the concrete how would i keep the rod fastened into the concrete? concrete epoxy? Just unfamiliar with inserting metal rods into concrete.

View splatman's profile


586 posts in 1302 days

#10 posted 01-16-2015 02:34 AM

That’s where the Figure-8 fasteners come into play. One end of the fastener is fastened to the shelf. The other end to the wall, to hold the shelf. As long as the shelf stays on, the rods will stay put.
After removal (like when vacating an apartment) the holes can be filled will wall patch compound.
For a permanent install, concrete epoxy is probably the way to go. Score the rods to allow the epoxy a mechanical grip.

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