Browse Forums Paving & Concreting 1 Apr 27, 2011 1:51 pm Chasing some info regarding concreting up against a fence - our concreter has suggested we place blueboard against the fence so the concrete can be poured directly up to it without damaging the fence (or for future replacements etc). But this being the case - what happens to the gap behind the blueboard in between the fence? Wont this just fill up with water? And cause rust and other types of damage to the fence? Ive attached a couple of pics for reference, can someone please suggest an option to do with the water, or if there are any other ideas instead of blueboard? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Cheers Re: Concrete against fence 2Apr 27, 2011 3:02 pm Well it shouldn't fill up with water as it isn't a sealed join at the bottom. It may fill up and drain away but it wouldn't stay there for good. As for rust. If the fence sheets are done properly then it won't rust as they will be sealed in the colorbond coating. The reason you have been advised in putting something against the fence is because the concrete will eat away at the coating and strip it off. You could also paint the fence with a bituminous paint as that will do the same thing but it will let you pour against the fence. The problem then will be as mention, if you need to replace it. Perhaps some color bond flashing cut to shape to fit perfectly against the fence corrugations and silicone against the fence to stop moisture getting behind it? Maybe you need to put a drain channel along the fence too if you're worried abotu teh water? Re: Concrete against fence 3Apr 27, 2011 6:25 pm The correct thing to do, is to remove the fence panels and place concrete boxing to the outside of the fence posts and concrete. Then trim off bottom of fence panels to new height and replace. Nice and neat....but it will cost you more unless you can do it yourself. Re: Concrete against fence 4Apr 27, 2011 6:36 pm I think the amount of water into the empty space left behind the b/b is negligible, or very, very low. This is just the surface water. I'd be much more worried if tehre is any chance for some under-surface water coming into play. For that reason, we'll leave a big gap (about 30cm) and insert ag pipe. We don't even want to do the ag pipe and then concrete over it - in case there are some maintenance (of the pipe) issue further down the track. My signature is distracting people from my wise posts ... Re: Concrete against fence 6Jul 06, 2020 12:12 am Hi Mike, hope you are doing well.. How did you go with this option of concreting against the fence by inserting a blue board to avoid touch the concrete with fence. I am almost in a similar situation and using pavers instead of concrete.. Did you notice water staying there in that small gap? Thank you Re: Concrete against fence 7Sep 01, 2020 11:46 am I'll be interested as well. Is there a sealer to deal with this gap? I am in a similar situation but have concrete sleepers abutting the concrete footpath. My sleepers are lower than the concrete footpath level. DIY, Home Maintenance & Repair I'm in WA and our sandy soils make drainage a bit easier but this is what I'd be doing. Dig down to your footings and let the wall dry out. Clean it all well by brushing… 1 5449 6 4569 Good on you for having a go I am the opposite of DIY (so will pay a builder) - our vibe is industrial/simple so current thinking is 150mm concrete and then internally is… 3 1359 |