Fence floor bracket/plate to concrete?

DorsetDude

DorsetDude

Spud
Suspended / Banned
Messages
7,018
Name
Keith
Edit My Images
Yes
Hi I want to fit an 8' 4" by 4" post into one of these mounted to concrete "floor"
AA bolt-down-bolt-type-3-1200x900.jpg

What do I need to use to mount the thing around the 4 holes in the base plate? Will an electric hammer drill be ok to drill the holes in the concrete? what fittings/screw/bolts do I need and what size drill bit? masonry bit I guess?
Do i need these fittings:? If so what holds them tightly in place in the hole?
AA bolt-down-bolt-type-3_01-1200x900.jpg


Thanks
 
Sleeve anchors like you have shown will do the job, you want to get the right length for the thickness of slab you are fixing into.

Just take your time and make sure all your holes are accurately positioned and true as they are a pig to remove.
 
bass_junkie83 said:
you want to get the right length for the thickness of slab you are fixing into.
Click to expand...
thanks, I have no idea of the thickness though unfortunately. Its the base of a brick pit thing that was once a large filter for a pond. the sides of the pit are bricks.

Hopefully the fittings may say what size bit I need. Maybe I can drill down in a random area of the base and see how thick it is or if it goes down 4" without hitting soil I know Im good.
 
It's good to test another area to determine the slab thickness. Anything less than 100mm for an ols slab would be unusual so you should be good. The drill size will be stated on the fixing packet, but it is generally the same diameter at the fixing itself. Cleaning out the hole with a blower is really important to make sure they work properly.

Hammer the fixing into the hole, put the fence post base in and put in the fixings. When you tighten it up it pulled the cone at the bottom up into the sleeve making it expand outwards and generating a high friction against the walls of the hole.
 
bass_junkie83 said:
It's good to test another area to determine the slab thickness. Anything less than 100mm for an ols slab would be unusual so you should be good. The drill size will be stated on the fixing packet, but it is generally the same diameter at the fixing itself. Cleaning out the hole with a blower is really important to make sure they work properly.

Hammer the fixing into the hole, put the fence post base in and put in the fixings. When you tighten it up it pulled the cone at the bottom up into the sleeve making it expand outwards and generating a high friction against the walls of the hole.
Click to expand...
I think the old slabs were 2" thick (50mm) and modern slabs generally about 32mm thickness.
 
If you don't know what you are drilling into, a more versatile but more expensive option is resin anchors
https://www.screwfix.com/c/screws-nails-fixings/resin-fixings/cat840022

Basically drill a hole, squirt n the resin, push in a threaded rod, let the resin set (about 20 mins) and then fasten your post holder down. The advantage being that it can work work with any length
 
Last edited:
An SDSPlus drill will make life a LOT easier when drilling relatively large holes in concrete. You should be able to hire one with a suitable bit for not-a-lot. Domestic type hammer drills will do the job but you'll be near the top end of its performance envelope.

I personally prefer THIS type of fixing into concrete but they do need a decent depth and strength of concrete to avoid it cracking under the strain.

When setting tall posts, I prefer to use a longer post and to set the bottom of it 18" - 2' deep in concrete/postcrete. Needs decent, treated timber for a long life.
 
Question, what is the post going to be part of / connected to? If it's just a standalone or part of a pergola it might be ok with that bracket, but 8ft of leverage is a helluva lot of leverage if say it's part of a fence and the wind gets up.
 
Two metres is the maximum permitted height anyway I believe. Those metal brackets are generally used with 3” posts, the fixings would have to be very good indeed to support a 4” post to 2m or more.
 
Cartus said:
Two metres is the maximum permitted height anyway I believe. Those metal brackets are generally used with 3” posts, the fixings would have to be very good indeed to support a 4” post to 2m or more.
Click to expand...


Possibly, although I reckon the bolt down and clamp in nature of the proposed fixing MIGHT make it a "temporary erection" (no sniggering at the back, please!) so rules are a bit different (or were a few years ago.)
 
Nod said:
Possibly, although I reckon the bolt down and clamp in nature of the proposed fixing MIGHT make it a "temporary erection" (no sniggering at the back, please!) so rules are a bit different (or were a few years ago.)
Click to expand...
In relation to fences 2m is the max - from the gov.uk website...

Planning permission is not required provided that: 1. The wall or fence is not more than 2 metres in height anywhere on your property except where it adjoins a road or footpath. In this case the height is restricted to 1 metre.

I'm assuming the post will be supporting something like a fence but otherwise I'm not sure - taller flag posts are allowed for example.
 
You must log in or register to reply here.
Back
Top