Thread: Dyna Bolts Vs Screw Bolt

man, i must be the slackest bastard around! I always use mechanical anchors on brick work and always through the mortar - I use a 12mm diameter anchor and attach it on the vertical mortar joint (thus avoiding any frog/extrusions on the bricks) - 12mm is always wider than the mortar, so drills slightly into the brick on either side, and I use an anchor that goes a minimum of 2/3rds of the depth of the brick wall. either screw in or dyna.

Only use it coz i use what i know, i've only used chemsets for particular problems - never had any failures in anything except ramset dynas - always know they are failures straight away on the plus side - pita to get them out though - good enough reason to use other methods!

Hi

Originally Posted by Fr_303

I need to secure a Pine Bearer to a brick wall.

Its a 3600mm long 140mm x 45mm Pine Beam

Is that all

Try a 8.6m 800mm x 75mm STEEL "C" channel!

This is supported by TWO dynabolts IN THE MORTAR at one end and the other end is supported by another steel C channel by two 12mm bolts. I only used the 12mm bolts because the holes were already drilled in the beam when supplied. [quote]

THERE IS NO OTHER SUPPORT anywhere along the beams length

what do you guys recommend I use Dyna bolts or Screw Bolts the bricks have 6 holes in them and I've had trouble with dyna bolts before.

Yes, you can have some trouble with Dyna bolts in the brick, because many times the end of the bolt is in the hole (as you probably guessed) and therefore there is no or very little grip.

Personally I have found, in the instances I have used (large) fasteners in bricks I have had better success with Loxins (drilled only a 10mm hole for the loxin body) they do seem to grip a little better, however they do need a much larger hole. Hence I would NOT recommend loxins in bricks and as you have found out Dynabolts are not too good either.

Can i use the dyna bolts in the mortar?

Of course you CAN. However you must do it with care. Don't do what my neighbours handyman friend did and put several Dyna bolts below ONLY the top course of bricks. The pressure of FIVE 10mm dyna bolts SPLIT the top row of bricks off the wall

Being a bricklayers son and being taught what my dad knew after a FIVE year bricklaying apprenticeship, I was advised to install fasteners in the mortar.

The ADVANTAGE of the mortar installation is that you will ALWAYS get at least the grip between the bricks and generally (although I sometimes have my doubts these days) a good grip also in the mortar itself.

For other corespondents to this post and or this thread PLEASE don't start the "mortar or the brick" theory, it's been done to death too many times already. We each have out own ideas/theories etc. Mine work for me and I guess yours do for you

Also what size bolts and how many should i use for that length?

If I were doing the job I would want at least 60mm in the mortar so you could use 100 - 120 mm Dyna bolts.

As mentioned earlier in this post I used TWO 10mm bolts at one end and TWO 12mm bolts at the other end.

This supports one side of an 8m long pergola made of heavy 8x2, 4x2 jarrah timber and is covered with alsynite and 50mm battens space 50mm apart.

This has now been installed and has NOT moved since installation five years ago

Whats the Best?

Hmmmm? it seems either / or, you get to choose

The attached photo shows the beam in its place.

As you will see in the photo I went for that "open, unencumbered look"

Probably a little too "springy" for a deck though

BTW keep in mind too that you are not having to clamp these beams REALLY, REALLY tight against the brick work. Obviously they have to be held firmly against the brick, but most, well virtually all of the "strain/stress" on this beam is going to be in a downward or shear direction. The Dyna bolts become essentially a means of "locating" them beam and preventing it from moving.

HTH

.

Originally Posted by pharmaboy2

man, i must be the slackest bastard around! I always use mechanical anchors on brick work and always through the mortar - I use a 12mm diameter anchor and attach it on the vertical mortar joint (thus avoiding any frog/extrusions on the bricks) - 12mm is always wider than the mortar, so drills slightly into the brick on either side, and I use an anchor that goes a minimum of 2/3rds of the depth of the brick wall. either screw in or dyna.

I won't get into the mortar/brick debate, especially seeing how in my region bricks are very rarely used. I would just recomend that you speak to either a Hilti or Ramset rep about your requirements.

Mick

gday fr_303

if you go with the chemical anchor route, can i make some suggestions that will keep the swear jar empty for a little bit longer ...

1. drill all the holes first and clean them out with a blast of compressed air &/or a stiff-bristled pipe cleaner

2. do a dry run to make sure it all lines up, and to 'load the programme' into your brain so on the night everything will go at least partially according to plan

3. if you encounter voids use the mesh sleeve as suggested by mick. your hole should go right through to the other side of the brick, and the sleeve should protrude slightly from both sides of the hole - crimp the back side so the stuff doesn't get pushed out the back; spread & flatten the front side against the brick so when you push the rod in the sleeve will stay in place

4. squeeze the poo in until you can see it in the hole say 20mm from the front edge. when you push the threaded rod in it will squeeze it out & around. make sure to leave enough for the width of the whaler plus a generous amount of thread to hole the nut & washer. don't bother trying to wipe it off the thread if you use too much. wait till it cures then hit it with the grinder, or widen the hole on the back of the whaler with a spade-bit

5. put the goo into the holes first, then come back and push the rods in (leave them sitting next to the hole so you can grab them quick). otherwise the nozzle will become blocked by the stuff curing before you want it to!

6. RUN don't walk don't mount the whaler until you've finished the beer you cracked to get over all the running.

7. if by the unfortunate grace of the blood-gods, or that you haven't paid enough pennance for success, put two nuts on the threaded rod and use the back nut to 'un-wind' the threaded rod out of its hole. do forty hail-maries and drill another one.

powers adhesives make a good 2-pack that can be applied from a standard caulking gun. the special nozzle that comes with it mixes the shyte as it gets squeezed into the hole. you can use standard gal threaded rod, 10-12 mm depending on your spacings.

regardless of the method, don't put a hole within at least say 300 of the corner of the brickwork. you can also make the holes in the whaler over-sized to allow for the slight movement of the timber.

r's brynk

Forgive me if I repeat anything that has already been said but there is much confusion here and everyone is telling you different things but no one has really hit the nail on the head.

First, NEVER NEVER EVER fix any load bearing anchor, mechanical or chemical to the mortar joints in brickwork. Mortar is often a weak mix of sand and cement that may have voids where you don't want them. Also, and especially with expansion anchors, it is a great way to start a crack in the wall.

Chemical is usable but in hollow brick you must use a metal mesh and make sure the holes are clean as BRYNK said. No adhesive sticks to dust and there is much dust in a freshly drilled hole, plus it is messy and expensive.

Dynabolts or any other expansion anchor often fail in hollow brick as the expansion mechanism may land in a void where there is nothing to expand against, unless you use a certain kind that is designed for reduced embedment applications and they work in the front face of the brick. Here is a link to info on this type.

http://www.powers.com.au/products/focus.aspx?bgid=17

Your application is perfect for screwbolts, but not just any screwbolt.

Choose a screwbolt that will engage the full width of the brick, so it has to be long enough to go through the 45mm timber, 5mm for a large square washer and 100mm of the 110mm depth of the brick, so the shortest screwbolt to use is 150mm long. Also rather than 4 at 12mm diameter you are better off using 6 at 10mm diameter, provided that the load required is met by this, you may need even more.

http://www.powers.com.au/products/focus.aspx?bgid=25

These screwbolts will give similar load capacities to chemical because the thread is engaged to the base material all the way down its length and the mode of failure is most often the brick. They are available in gal too.

If you hit the void this is not such a problem as you have the front and back brick faces engaged and it will hold up.

One last advantage that is often under rated is that screwbolts are a through fixing, you can drill through the timber and fix the anchor without moving the timber out of the way to set the fastener, often the proturding studs are not quite lined up with the holes, (PITA).

Ramset or Hilti may have similar products but these are the ones I am familiar with having been technical advisor for a distributor of theirs for many years but there is no longer any affiliaition.