Vijay

I asked how they calculated and if I co do a backdrop and got this reply: Following talks with the surveyor an in chamber backdrop would not be recommended. We happy with the proposal as it stands currently. 1:36 was worked out by 540 divided 15 So I'm going with what they've said and cracking on tomorrow!

Spoke to the BCO and then sent him this email: As per phone call, please find the figures I've used for calculating the drainage fall. The one we looked at at the front is 15m long and the invert between the two ends is 540mm. Using this site http://www.wyre.gov.uk/info/200316/building_control/166/basic_guide_to_calcu and using the calculator on this site http://www.pavingexpert.com/gradient_01.htm they both tell me the fall I actually have is just under 1:28. For a 1:40 fall I would need to reduce it to a 375mm invert and a 1:80 would need to be reduced to a 188mm invert. So over each metre that's a 25mm drop for 1:40 and a 12.5mm for a 1:80 drop So currently my fall is too much of a slope and needs to be reduced to a gentler fall which is why I had those ideas including a chamber backdrop. Their reply: Following a discussion between surveyors in the office and your email we can confirm we would be satisfied with the proposal as it currently is onsite and per information provided. From the information we calculate 1:36 fall which is acceptable as 1:40 is the ideal recommendation. However should you want to achieve 1:40 requirements which is optional, one end will need be raised or lowered accordingly to achieve the correct gradient. What do you make of that????????????????

Thank you So can I just increase/decrease the mortar joint depending what I need? (between 270 and 300mm) Is there any other way of doing this in single skin/block upright (as it's less blocks for me to lay) or would that involve cutting blocks? I have a Stihl cut off saw if I need to cut blocks

Yep, seen them cut exactly that way and then they polished any edges using another attachment on the angle grinder

My provider insists on an outside wall (if on the house), either externally in a box or internally on an external wall. They said no way to having it further within the house even with smart meters.

Is there any noticeable difference on soundproofing/deadening between the different blocks when used for internal walls? I've attached a basic sketch of the internal walls I need to build. The yellow are sleeper walls to support the B&B floor which I've been told I can do in 100mm blockwork apart from where 2 beams meet where it needs to be a 200mm wall (so I was just going to double up the block on those points). The red are internal load bearing walls which go up 2 floors. I'm going to use concrete blocks for the internal rising and sleep walls. I need to build up to between 270 and 300mm so how do I do that with standard sized blocks? I assume I'd have to cut the blocks?

Inside of an external wall?

Not Clive Lindsay is it?

I tried contacting them many times but they were useless at getting back to me and then gave me dead email address - strange way to do business!

Looks perfect. I've emailed my BM's

Am I right in saying there is basically 3 types of standard block: Dense concrete block - used underground/rising/sleeper and load bearing walls Lightweight/medium concrete block - used for non load bearing walls and beam and block flooring Aerated (breeze?) - internal non load bearing walls Is there another block that can be used internally for load bearing walls that aren't as heavy as dense concrete blocks? Thanks Vijay

Would you be able to use one of these? http://www.marmox.co.uk/products/thermoblock

Thanks for confirming that I got my calculations right. Good tip for the level, I'll do that I'm going to call him in the morning and have a chat, think it's the best solution cos he'll be coming back to check it anyway. Cheers for the link Barney

Desperately need some advice and guidance guys and girls. BCO came round and he's a really nice bloke who checked the foundation depth before. He is perfectly happy with the fall and said I would have no problems. Even when I pointed out the fall I have is 1:28 he was adamant that it is fine and I've worked things out wrong. He commented that cos it's in plastic, that things slide as Oz07 suggested. If it was clay it would be a different matter. HOWEVER I believe he's worked things out wrong cos when he explained it, he said for every metre you go out, you drop 40mm - but surely that's a ratio of 1:25? I said 3 times that I think he's worked it out wrong and I need a shallower fall but he insisted. The pipe run is 15m and I have a fall of 540mm between the IC and manhole. 15,000/540 = 27.78. If I want a 1:40 fall, then I need 375mm between the IC and manhole - have I worked that out correctly??? I'm going to send them an email to check again but it's awkward that I'm telling a BCO that he's wrong (if indeed he is), so am looking for any advice before I do

Hi Ed, I know I will get shot for this but I bought a Chinese jobbie off Ebay and it's been spot on so far (famous last words). I'm afraid I never lend my tools out (hard and fast rule I've always stuck to) but I'm guessing you might be in Milton Keynes which isn't that far from my plot. So if it's something we could do on a weekend day, I might be able to pop up (I live in London) and help you Vijay

Why do you say that, surely it can be rodded from both top and bottom inlets and the rod would reach to the bend??

I assume your suggestion was to have a concrete chamber?

Chamber is plastic so I think I could do the same as the pic in my above post?

Just thought it would help if anyone does a future search Thanks everyone. The suggestion of speaking to the BCO makes sense and I'll see what he's happy with - would be brilliant if he was happy with the fall and can be rodded from both ends of the 15m run . I can go armed with a backdrop and see what he says about it. Wouldn't be too much trouble to do this and get what ever fall the BCO asks for: http://www.pavingexpert.com/drain05.htm

I'm struggling on a drain run and only have a fall of 1:28 (the fall is 540mm over 15m). I can cut the concrete of the foundation if I really have to but I wondered if there's any tips to lower the incline? The manhole that I'm connecting into has a 160mm inlet, can I use a 160 to 110mm level invert reducer and have it so the 110mm is at the top? That could buy be 50mm. The Floplast mini inlet chamber's side inlet is 100mm above the outlet. Am I allowed to use the side inlet to change direction if i don't have any flow into the main inlet (that flows straight through to the outlet). If I could, that could buy me 100mm. A mate suggested using a couple of say 15 degree elbows to give the pipe a kick down. I think the idea would work but don't know if it's allowed or be a potential blockage place. I also wonder how that would affect rodding.

As I said, not the end of the world to have to down the corner of the dining room which is what's been drawn. I'll be having a rethink as I do the drainage pipes

That's exactly where I saw it

Nick you bust my bubble!!

Might be of some help http://www.pavingexpert.com/drain12.htm

A rest bend. What's the difference between a rest bend and a settlement rest bend?