Formwork to allow fence post shoes close to wall

[Steve111111]

I plan to lay some concrete. Once set I'll be putting up a fence on either side. The fence will run along the red line in the attached pic and also along where the timber is.

For the fence posts I'll be using bolt down shoes.

Looking for advice on the yellow line in the pic. I had planned to create the form using timber on the left (red line), top (yellow line) and right (timber in pic) and for the bottom I'll just use the path.

Then I realised that if I want the fence right against the wall at the back I can't have that timber (yellow line) there because the there would be empty space left when I remove the form. And with the shoes I'd need to have them in a bit from the edge of the concrete too so the fence would be even further away from the wall.

If I don't have the yellow line timber there then I'm not sure how easy it will be to screed the concrete. There's a fall from right to left which I want to maintain for rainwater drainage, and I had planned to run the screed board along the yellow line and path (at the bottom of the pic). So the screeding would be done from right to left and not top to bottom.

Should I shorten the yellow line so there is empty space where I want to put the shoes, and screw the yellow line to the wall?

 

[Deluks]

A bit confusing.

Anyway, you definitely don't want the post shoe in the firing line of the downpipe shoe.
You should form an aco drain against the wall, bury a gully into a 100mm pipe or extend the pipe down into the garden area to the left.

Fence right against the wall isn't a great idea, it could trap damp behind it, or more like trap leaves and rubbish that will hold the damp.

The post shoe can be bolted down in the centre, some have a hole, or you can drill one. That way you won't need to fix to the edge of the concrete back against that wall. You could always fix the fence to the back of the posts, instead of in between.
Thicken the concrete to 150mm around the edges, to give plenty of depth for the bolts.

 

[23vc]

Don’t really get the bolt down fence either, surely you can just dig down and set them properly, particularly if you’re pouring concrete anyway, seems a no brainer.
Can’t you screed the concrete on the shorter span, working off the timber on the right to another timber you set on the left at the correct (lower) height?

 

[Steve111111]

Don’t really get the bolt down fence either, surely you can just dig down and set them properly, particularly if you’re pouring concrete anyway, seems a no brainer.
Can’t you screed the concrete on the shorter span, working off the timber on the right to another timber you set on the left at the correct (lower) height?

I was thinking it would be easier to screed on the long side as there is a fall from right to left. If it was flat then yeah I would definitely screed on the short side.

 

[Deluks]

You don't need as much fall as the photo suggests. I agree with using the short side. 15mm will be enough if you get it flat.

 

[stevie888]

I'd set posts first using concrete posts for long life., set my gravel boards in accurately and then screed off them using a tamp with an off set end.

Or if you prefer set timbers into the post rebates to use as forms and drop your gravel boards in after, whichis probably easier.

 

[Steve111111]

Just so I'm not misinterpreting short side and long side with regards to screeding, when saying to screed using the short side do you mean to run the screed board along the longer forms i.e. in the photo I would start at the top by the wall (where the yellow line is) and work my way down to the bottom of the pic (where the drain cover and path are)?

I've very limited experience with pouring concrete but I recall someone telling me before it's harder to screed on a slope, so screed from high to low if possible. But maybe because my slab will only be 3m x 2m it shouldn't be a problem?

 

[23vc]

Screeding means moving a straight edge in a sawing and tamping motion, along 2 parallel timbers set at the right height. Slope isn’t going to be an issue unless you mix it incredibly wet and it’s only a tiny fall.
So like I say, I’d first set your 2 screed “rails” (timbers) at exactly the right height, level etc. use pegs into the ground or whatever. Then you’re good to pour, and screed along them. Then if you screed along the top timber and a new timber where the red line is, you can concrete right up to the white wall at the top of the pic, which I thought was your original aim…

 

[Steve111111]

Thanks for clarification

 

[Steve111111]

While I'm here, and I know it's a slightly different topic, but if I go with using post shoes (I honestly think I'd be incapable of accurately installing the posts directly and getting everything lined up correctly including a gate) what size bolts should I use? And should I use concrete bolts directly into the concrete or something different? Recommended size?

 

[23vc]

I honestly would say set them into the ground instead. If you use a dry mix, you can mess about with them as long as you like, get some temporary timbers in, or wedge with bits of brick or whatever you like, get them spot on. then tip a bucket of water into it once done and leave it overnight.
If you do want to use bolts, something like m10 at least 150mm but steer well clear of the edge of the slab as it’ll break out when you screw them in as they’re bigger than the hole so expand it out as they go in

 

[Steve111111]

Any thoughts on me using anchor bolts instead of concrete bolts for the post shoes? I had planned to use concrete bolts but was chatting to someone down the pub Saturday night who said anchor bolts would be better. Looking for a second opinion.
BTW the posts (and fence panels) are steel so not heavy concrete ones.

 

[Steve111111]

Forgot to add that the holes on the shoes are 13mm diameter

 

[Deluks]

Forgot to add that the holes on the shoes are 13mm diameter

What shoes are you referring to?

If it's a metal fence post, then you can just concrete these in. Use 150mm square pieces of foam insulation or just any old polystyrene, or make up a little box where the posts will go, set just below the intended concrete surface.
Concrete over the lot, after a couple of days, break through the concrete and dig out the foam, then you can dig a hole for you posts, and concrete them in.

Might be easier to dig the post holes first, depending on what tools you have and ground conditions.

Just an idea.

 

[Steve111111]

I'm putting a fence either side of a shed. One side already is concreted (first pic). There will be a gate going over the concrete path on the left and a fence across the lighter concrete. Hence the need for post shoes.
The other side of the shed (second pic) will have a gate going across some of the cobble stone and a fence across the rest of the cobble stone and the rest of the way over new concrete.

The shoes are metal and will support metal (galvinised steel) posts. The concrete is already there at the back of the shed so I think it would be easier to just bolt down shoes instead of digging up the concrete.