Discussion:
Bolting fence posts to hollow brick - best fasteners to use?
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Darro
2004-04-20 18:45:57 UTC
Permalink
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"?

Although the load on the brick and fasteners would be quite light, I'd
like to be reasonably sure that they wouldn't easily pull out or break
out of the brick.

I've talked with Hilti about their reddi-rod/tube screen/epoxy system
which looks pretty good but is far too costly for a small job like
this because I'd have to buy excessive minimum quantities and
epoxy-injection equipment.

I know that it may limit my options, but the fasteners also have to be
all-stainless steel.

Any helpful suggestions would be much appreciated.

Darro
Doug Miller
2004-04-20 19:07:04 UTC
Permalink
Post by Darro
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"?
Brick doesn't have much holding power, so you should fasten to the mortar, not
to the brick. Drill holes in the mortar and insert lead anchors (available at
any hardware store). Then run screws or bolts through the posts and into the
anchors.
Curmudgeon
2004-04-21 00:20:54 UTC
Permalink
Look at HD or Lowes for Tapcon connectors which are specifically designed
for concrete, brick & cinder block. They're like a cross between lag bolts
and screws. You can do it with a drill and their driver set.
Post by Darro
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"?
Although the load on the brick and fasteners would be quite light, I'd
like to be reasonably sure that they wouldn't easily pull out or break
out of the brick.
I've talked with Hilti about their reddi-rod/tube screen/epoxy system
which looks pretty good but is far too costly for a small job like
this because I'd have to buy excessive minimum quantities and
epoxy-injection equipment.
I know that it may limit my options, but the fasteners also have to be
all-stainless steel.
Any helpful suggestions would be much appreciated.
Darro
Nehmo Sergheyev
2004-04-21 00:54:05 UTC
Permalink
- Darro -
Post by Darro
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"?
- Nehmo -
Do you mean hollow concrete block? Sometimes called a Concrete Masonry
Unit (CMU)? Or do you mean cored brick? In any case, are you placing the
4x4s against a wall or are you meaning to support the posts from the
bottom?

- Darro -
Post by Darro
Although the load on the brick and fasteners would be quite light,
- Nehmo -
What's the load? Is this a fence?

- Darro -
Post by Darro
I'd like to be reasonably sure that they wouldn't easily
pull out or break out of the brick.
- Nehmo -
You're not specifying how strongly you want to secure the 4x4s or what
your purpose is. So "reaonably sure...easily" isn't clear.

- Darro -
Post by Darro
I've talked with Hilti about their reddi-rod/tube screen/epoxy system
which looks pretty good but is far too costly for a small job like
this because I'd have to buy excessive minimum quantities and
epoxy-injection equipment.
- Nehmo -
I don't know about the system you refer to, but you certainly can buy
epoxy in small quantities.

- Darro -
Post by Darro
I know that it may limit my options, but the fasteners also have to be
all-stainless steel.
- Nehmo -
Not really. There's a stainless steel version of almost everything. But
why do you require SS? If you're worried about corrosion, Deck-mates or
galvanized may be suitable.

BTW, to respond to another post in this thread, don't secure your
fasteners to the mortar between the bricks. Mortar is more likely to
crumble out and fail than the brick or the concrete.
--
*********************
* Nehmo Sergheyev *
*********************
Darro
2004-04-21 03:03:19 UTC
Permalink
On Wed, 21 Apr 2004 00:54:05 GMT, "Nehmo Sergheyev"
Post by Nehmo Sergheyev
- Darro -
Post by Darro
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"?
- Nehmo -
Do you mean hollow concrete block? Sometimes called a Concrete Masonry
Unit (CMU)? Or do you mean cored brick? In any case, are you placing the
4x4s against a wall or are you meaning to support the posts from the
bottom?
*Darro*
I mean hollow brick (not concrete, and defined as a brick with uniform
1-1/2" walls and a hollow core). The posts will be placed against the
wall and will be supported only by the horizontal fasteners.
Post by Nehmo Sergheyev
- Darro -
Post by Darro
Although the load on the brick and fasteners would be quite light,
- Nehmo -
What's the load? Is this a fence?
*Darro*
The fence would be about 18" high.
Post by Nehmo Sergheyev
- Darro -
Post by Darro
I'd like to be reasonably sure that they wouldn't easily
pull out or break out of the brick.
- Nehmo -
You're not specifying how strongly you want to secure the 4x4s or what
your purpose is. So "reaonably sure...easily" isn't clear.
*Darro*
This is not a heavy-duty or high-risk installation, just a typical
residential fence which should be able to bear the weight of the fence
(estimate 40 lbs per bolt) and an adult climbing over it (estimate 50
lbs per bolt).
Post by Nehmo Sergheyev
- Darro -
Post by Darro
I've talked with Hilti about their reddi-rod/tube screen/epoxy system
which looks pretty good but is far too costly for a small job like
this because I'd have to buy excessive minimum quantities and
epoxy-injection equipment.
- Nehmo -
I don't know about the system you refer to, but you certainly can buy
epoxy in small quantities.
*Darro*
If epoxy is the way to go, I'll look for small quantities.
Post by Nehmo Sergheyev
- Darro -
Post by Darro
I know that it may limit my options, but the fasteners also have to be
all-stainless steel.
- Nehmo -
Not really. There's a stainless steel version of almost everything. But
why do you require SS? If you're worried about corrosion, Deck-mates or
galvanized may be suitable.
*Darro*
There are non-technical reasons why the fasteners have to be all
stainless.
Post by Nehmo Sergheyev
BTW, to respond to another post in this thread, don't secure your
fasteners to the mortar between the bricks. Mortar is more likely to
crumble out and fail than the brick or the concrete.
*Darro*
The mortar is actually cement, but I'll keep your warning in mind.
Nehmo Sergheyev
2004-04-22 16:47:58 UTC
Permalink
- Darro -
Post by Darro
Post by Darro
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"? ...
I mean hollow brick (not concrete, and defined as a brick with uniform
1-1/2" walls and a hollow core).
- Nehmo -
I'm not clear what kind of masonry unit that could be. Your ' 1-1/2" '
apparently means 1.5 inches. That sounds like it could be a concrete
block, but you say it's not concrete.

- Darro -
Post by Darro
The fence would be about 18" high.
The posts will be placed against the
wall and will be supported only by the horizontal fasteners.
- Nehmo -
You could use polyurethane glue alone without any fasteners. There are a
few brands out there.
http://froogle.google.com/froogle?&q=polyurethane+glue
I don't mean the hot-melt kind. Popular Woodworking has an article:
http://www.popularwoodworking.com/features/fea.asp?id=1064

But if you are decided on using metal fasteners, 1.5" thick brick (if it
is brick) may not offer much to grab on to.

You could drill a œ " hole in the brick to its cavity using a masonry
bit (a rotary hammer with an SDS bit would be best, but you probably
don't have that), and use long Stainless Steel toggle bolts going all
the way though the 4x4, through your hole in the brick, and into the
cavity. What makes a toggle bolt toggle is actually the winged anchor
part, the nut. The machine screw (bolt part) can be a stock 6"x Œ" SS
bolt. (I suggest 6" long because 3 œ" + 1 œ" = 5", the 4x4 + the wall
thickness of the outside of the brick to its cavity.)

Another method would be to drill all the way through the masonry wall
and use an nut and washer on the opposite side.

If the "brick" is really concrete or slump block, you have more options.
Go to the hardware store and have them explain what's available.

But basically...

Pre-drill the 4x4 with all the holes. An 18" high 4x4 could take two or
three fasteners.
Screw-in a suitable lag screw in each hole so that only perhaps Œ" of
the point extends through.
Place the 4x4 in position against the wall. Then tap it into the wall
using a scrap block between the hammer and the 4x4. You should've made
small marks on the wall where the screws protruded.
Use these marks to indicate where to drill holes. Drill them with a
masonry bit or some other suitable tool.
Place plastic or lead anchors in the holes.
Put the post up and run your screws in.

*Darro*
Post by Darro
The mortar is actually cement, but I'll keep your warning in mind.
- Nehmo -
The terminology is confusing:
Mortar is the bonding material between bricks or blocks. It is made from
fine aggregate (sand), and either regular cement or lime by itself and
water.

Cement, an _ingredient_ of concrete and mortar, typically consisting of
silica, alumina, lime, iron oxide and magnesia.

Concrete is often incorrectly referred to as cement.
--
*********************
* Nehmo Sergheyev *
*********************
Robert Allison
2004-04-21 01:10:15 UTC
Permalink
Post by Darro
Would anyone be able to suggest how I can bolt a few 4x4 wood posts to
hollow brick with a wall thickness of about 1-1/2"?
Although the load on the brick and fasteners would be quite light, I'd
like to be reasonably sure that they wouldn't easily pull out or break
out of the brick.
I've talked with Hilti about their reddi-rod/tube screen/epoxy system
which looks pretty good but is far too costly for a small job like
this because I'd have to buy excessive minimum quantities and
epoxy-injection equipment.
I know that it may limit my options, but the fasteners also have to be
all-stainless steel.
Any helpful suggestions would be much appreciated.
Darro
Since brick doesn't have much holding power and is brittle,
expansion anchors are out. They will have a tendency to break or
crack the brick. Epoxy is your best solution and you don't have to
have the expensive setup that Hilti or Western Fasteners uses. Call
around to your area concrete products vendor. They have epoxy in a
caulk tube for around $12.00. One tube will do several holes. The
only drawback to these tubes are the viscosity only allows you to do
vertical holes. It will run out of a horizontal hole.

Here is the website for one such creature:

http://www.sikaconstruction.com/tds-cpd-SikadurAnchorFix2-us.pdf
--
Robert Allison
Rimshot, Inc.
Georgetown, TX
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