large floating shelves on a brick wall.

adranovs · Jul 18, 2018

I am making floating shelves from 3 x 9 joists. The shelves will be 52 inches long so they are heavy and will hold heavy large objects. The brick wall is over 100 years old, but I mounted my kitchen cabinetry to it and it holds great. I decided to do the job with 3/4 inch rods and want to directly insert them into the brick about 2-3 inches. There shouldnt be wiggle room for the rods in the brick so that the shelves do not end up sloping down. Will a 3/4 masonry bit in brick create a hole that will fit 3/4 rod snugly or do I have to go bigger like 13/16?

Thanks.

L Vanice · Jul 18, 2018

Most masonry bits drill oversize holes, and the holes may not be straight if you use a hand-held drill. A slightly oversize crooked hole may feel snug at first. I think a 2-3" blind hole is entirely too shallow for the described purpose.

Securely fastening things to a brick wall was traditionally done by passing a metal bolt through to the other side of the brick, placing a large washer, often decoratively shaped, over the bolt end and securing with a nut. I have seen those washers and nuts on the outside of old brick and stone buildings.

Larry

WizardOfBoz · Jul 18, 2018

Boy, I'd be leery of putting heavy shelves in like that. With cabinets, there is height working with you. So the bolts only are subject to shear. With shelves, you don't have any material above or below, and so there's a significant bending moment at the wall. This is supported by the bottom shelf edge along the wall, which increases the tension on the bolt. So, assume that your rods are centered, and put 100 pounds on the shelf about 6 inches from the wall, you've added 400 lbs of "pull out" force. If this is going to be a showcase type shelf, maybe. If this is going to be a high-duty cycle shelf (with heavy objects added and removed all the time), then you've got dynamic loading to consider when you throw a heavy part on the thing. This is the reason for the steel plate behind the wall mentioned above. Not sure that masonry screws or anchors will hold, especially in high-duty cycle. I'd want the support plates in back, and a cantilever truss support (like in the photo below) below the thing to minimize the amplified pull-out force.

ScraperCarl · Jul 18, 2018

adranovs said:
I am making floating shelves from 3 x 9 joists. The shelves will be 52 inches long so they are heavy and will hold heavy large objects. The brick wall is over 100 years old, but I mounted my kitchen cabinetry to it and it holds great. I decided to do the job with 3/4 inch rods and want to directly insert them into the brick about 2-3 inches. There shouldnt be wiggle room for the rods in the brick so that the shelves do not end up sloping down. Will a 3/4 masonry bit in brick create a hole that will fit 3/4 rod snugly or do I have to go bigger like 13/16?

Thanks.

Over 100 y/o wall can be there is little if any cement in the mortar and the bricks are soft ones - will be good to check. Then a 3/4 bit will vibrate the bricks and unseat them and you will get cracks. Use "anchoring cement". The good anchoring cement takes 15 minutes to set as hard as rock. I use rebar or threaded rod and we have some heavy stuff hanging on the walls like that.

thermite · Jul 18, 2018

ScraperCarl said:
Over 100 y/o wall can be there is little if any cement in the mortar and the bricks are soft ones - will be good to check.

Classical "brick" homes had two parallel planes of wall, brick ties between. UK still builds them that way. US practice is more often "brick veneer", ONE layer, only, wood or sheet-steel studs, now and then cinder block behind.

The brick is not all that much stronger as to side loads than what they are.

Neatly stacked fried dirt, mortared to compensate for irregularities. One man, one sledge hammer, those walls can be collapsed back into a pile of rubble in a New York Minute

Good stand-alone shelving tied-in can strengthen such a wall.

The reverse? Not so much. Don't confuse a hard surface with overall strength.

Pure "compression" load is one thing. "Bending" loads on masonry? Yah. Reinforced concrete. If/as/when/where planned, designed, and correctly implemented FOR that.

Laid-up brick?

Gotta be kidding, right?

adranovs · Jul 18, 2018

Thanks for the info Larry.

adranovs · Jul 18, 2018

Thats helpful. I was thinking of adding two corner 4x4 triangular brackets where the two sides will be mounted onto two walls and the steel connecting them will be recessed into the shelf. One would go on each side of the shelf. This should decrease the forward moment a fair bit. and the middle will be supported by several 3/4 rods going into the brick and into the shelf.

thermite · Jul 18, 2018

L Vanice said:
I have seen those washers and nuts on the outside of old brick and stone buildings.

Larry

Yes, those were once common, "star" shapes especially, and are still seen all over New York City, several older cities in New England, Philadelphia or Pittsburgh, PA and other places where brick has long been a staple for buildings.

And many of those were preventing that wall falling over by connecting to a steel, wrought-Iron, or even heavy timber structural member or turnbuckle tensioner working WITH a beam on the other side of the wall, too.

NOT so many are putting any load into or ONTO that wall.

One "just doesn't" cantilever anything of significant mass off a brick wall. They do not bend gracefully.

PeteM · Jul 18, 2018

Another way to beef up a floating shelf system is to secure some thin cable to a few ceiling joists and run down it through the shelves (secured below each shelf). This can be near-invisible from a distance and dramatically increase the load-carrying capacity.

Curious what heavy object wants a 3" thick shelf?

boslab · Jul 18, 2018

Drill slightly larger and use stud bar, clean the hole with a hole brush, blow the dust out and squirt polyester epoxy in, stuff the rod in, when set it will pull the wall apart before letting go.
Mark

dalmatiangirl61 · Jul 18, 2018

boslab said:
when set it will pull the wall apart before letting go.

With 100 year old bricks, yes, yes it will pull the wall apart.

As mentioned above, old bricks are likely to have soft centers, it is not because of age, but because of the firing process used back then. Masonry restoration is one of the hats I wear, the op's plan is ill conceived and ill advised.

DDoug · Jul 18, 2018

dalmatiangirl61 said:
With 100 year old bricks, yes, yes it will pull the wall apart.

As mentioned above, old bricks are likely to have soft centers, it is not because of age, but because of the firing process used back then. Masonry restoration is one of the hats I wear, the op's plan is ill conceived and ill advised.

I'm on the other end of that process....I bought 88 triaxle loads of brick buildings for driveway base.

I only took soft red brick buildings.

Every time the dump bed went up, out slid a whole 20 tons of clean bricks,
all the mortar was knocked clean.
You could have pulled them from the pile, and relaid them as new.
On the loading end, simply touching the wall with the excavator brought the whole wall down, the mortar was like cottage cheese.

WizardOfBoz · Jul 18, 2018

boslab said:
Drill slightly larger and use stud bar, clean the hole with a hole brush, blow the dust out and squirt polyester epoxy in, stuff the rod in, when set it will pull the wall apart before letting go.
Mark

Yes. But that brings up the key point, which others have brought up. The shelves, installed like this, might just pull the wall apart. Unless one knows how the wall was built, understands the materials used, and can count on the standards used to specify materials and workmanship, the wall may have the strength of "fried dirt" to use my kinfolk thermite's phrase. Second, using an impact masonry drill and bit can loosen the mortar joints as can age (I like dalmationgirl's point that, after dumping out bricks from a demoed wall, they were "mortar free". That is, the old mortar joints couldn't even hold mortar bits on. Never mind holding the wall together.

I'd be very circumspect about using a brick wall (which is, in general, excellent in compression) for service where it had to resist a moment.

Bobw · Jul 18, 2018

Simply put.. I'd move the load to the floor...

My better half is a school teacher and has a GIANT closet. Teachers have wardrobes like royalty and Kardashians.
Except its bought on E-bay and in thrift stores. Her closet is is only 18 sqrft smaller than the bedroom I grew up in.

The racks were attached to walls. New "Manufactured home :rolleyes5:

" in 2002 double wide
Its a F'n Trailer, I don't care what she says, ehhhh yeah I do.

Her Dad fixed them years ago.. Then I fixed them, then they all came a tumbling down again and I went
nuts. 6 million screws and brackets and what not... And then once again, One wall came down and
all the other walls came crashing down AGAIN!!!!! Some of the screws ripped out of the wall, some
of the brackets BROKE.

So no more of this wall stuff. Last week I re-did her closet. All the forces now go TO THE FLOOR!!! Pics below.
Just framing timbers and 1" pipe.. But its not going to fall, I had my fat ass up there jumping up and down, its
not going anywhere.

My suggestion, do something to get the forces into the floor, OR coming down from the ceiling if you've got something
solid up there.. It doesn't have to look like crap, like my closet.. Black hammer tone paint on crappy mild steel
can sort of look like cast iron. Do something fun.. Picture frames or get some neat designs plasma cut. Some cool
scroll stuff.. Your imagination is the limit.. Floating shelves, whatever, you can have a lot more fun with it, and
make sure it doesn't take your wall down at the same time.

dalmatiangirl61 · Jul 18, 2018

bosleyjr said:
I like dalmationgirl's point that, after dumping out bricks from a demoed wall, they were "mortar free". That is, the old mortar joints couldn't even hold mortar bits on. Never mind holding the wall together.

That was actually Doug that made that point, but it is the nature of old (most likely) lime based mortar. It works great in compression, but has ZERO grip on the bricks in tension. Portland based mortar was not commonly used 100 years ago, it was there, but traditional lime mortar was the norm, and depending on location, even the lime had differences.

EPAIII · Jul 19, 2018

Three words: Don't do it.

DDoug · Jul 19, 2018

dalmatiangirl61 said:
That was actually Doug that made that point, but it is the nature of old (most likely) lime based mortar. It works great in compression, but has ZERO grip on the bricks in tension. Portland based mortar was not commonly used 100 years ago, it was there, but traditional lime mortar was the norm, and depending on location, even the lime had differences.

Eggzachary !

Any newer building with hard brick, when dumped out would hold together as wall sections, and I only sent those over the bank, for "gross fill".

adranovs · Jul 19, 2018

To PeteM. The shelf is just for books and such. The 3 inches is because thats the size of the joists. They were recovered from a demoed old townhouse in the neighborhood. The design is all exposed brick with old brick archways and exposed window beams that are also made from joists material. I just finished sanding and staining the joist shelves and they look spectacular.

thermite · Jul 19, 2018

adranovs said:
To PeteM. The shelf is just for books and such. The 3 inches is because thats the size of the joists. They were recovered from a demoed old townhouse in the neighborhood. The design is all exposed brick with old brick archways and exposed window beams that are also made from joists material. I just finished sanding and staining the joist shelves and they look spectacular.

Good to know. "Books" are lighter than Zeppelin's dirigibles, after all.

Now we can say:

"Remember adranovs from New York?

He surely had a fine sense of aesthetics for a person without the least lick of common sense about structural matters."

dalmatiangirl61 · Jul 19, 2018

thermite said:
"Remember adranovs from New York?

He surely had a fine sense of aesthetics for a person without the least lick of common sense about structural matters."

Got a link to that reference? Google ain't finding it.

Brick wall collapse, looks to me like he did more than just remove 1 brick
Old building collapses in UK when engineer removes single brick - YouTube

Brick building demolition, just a little poking and it crumbles
Leominster: Columbia Demolition: Unstable Wall Removal (1 of 2) - YouTube

large floating shelves on a brick wall.

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