Anchor bolts..?

[mondyman]

This might come across as sounding stupid lol...but what size anchor bolt do i use for the 3" x 3" bolt on met post...There are so many i cant work out what size would suit me..
Im putting a fence up on top of a 9 ft wall ( the wall is 9" thick )on one side is my garden and the other is a 6ft drop so i want the fence to be absolutely solid ( u know what kids are like ! )
It says on the met post to use M8 X 10mm , what does this convert to if i want to us anchor bolts......
Cheers

 

[seaangler]

i would think that that would refer to a M810L rawlbolt

8mm diameter bolt in a shield requiring a 14mm hole with 10mm capacity

are the bricks sound ??? you may be better using a chemical fix which means you can use a longer length of stud in the brick and with little chance of splitting one of the bricks

 

[JohnD]

What is this chemical fix? How is it used? Can you put a screw into it? I plugged near the edge of some blocks and spalled them off recently.

 

[breezer]

its a poxy resin, you fill hole say 50% then insert fixing, leave to set then use fixing

 

[JohnD]

Does "fixing" mean stud, or could it be a plasplug? I want to screw some wooden window trim to the wall so I can take it off for retreatment later.

(I put up a query on the "building" page but got no bites)

 

[breezer]

if by plas plug you mean a red,yellow or brown bit of plastic to which you rotate clockwise a threaded peice of metal with a large head then no.
That defeats the object. poxy resin moulds to the shape / tread of the fixing inserted.

but for your job why not just use screws and rawplugs

 

[JohnD]

I used plasplugs and screws (did you mean the brown fibrous plugs?) but the blockwork only projects about 35mm beyond the window frame, then is felt, battens and hung slates; which the trim conceals, so my holes were too near the edge and several of them spalled off when I drove the screws in

 

[breezer]

drill a deeper whole and use longer screws

 

[mondyman]

I was going to use the new THUNDERBOLTS , they are like self tappers for the met posts u drill a pilot hole and torque them in using a spanner , if i use them and epoxy will that be strong enough ??
The bricks look new or nearly new and arnt crumbling so if i get a reasonably long bolt it should be ok...shouldnt it!

 

[breezer]

try it and see.

but are not metposts wood (the base, be it spike, platform or replacement is metal, or is it the platform ones you want to secure?)

 

[Deluks]

Thunderbolts do provide a strong fixing. They don't need any resin though. You could use a combination of chemfix stud in the centre of the metpost, and thunders on the outside 4 corners, or vice-versa.

Make sure the inside stud is very low down though, as the wood post would be resting on it. An advantage of this is that the bottom of the timber is raised by a few mm, which might help prevent any future decay caused by water collecting at the bottom.

Best thing to do is drill the hole, cut a piece of studding slightly longer than depth of the hole, attach a nut and washer to the end before sinking it into the resin. (Don't let the washer or nut get any of the resin on it)

When the resin has set, unscrew the nut and washer, put metpost over the top and loosely replace nut. Then mark the other 4 holes for drilling. Remove metpost, drill, replace metpost, attach thunderbolts. Job done.

I found it tricky to drill in the exact right place with an 8mm bit, start the hole with a smaller 4 or 5 mm bit, then enlarge with the 8mm. I used sds hammer action but that might be too much for the top of a brick wall so a normal drill might be better.

The thunderbolts will be very snug, I had to screw mine in flush by hitting the spanner with a mallet!