Capable Noob

Thanks everyone. They're 9" timbers (which are the bottom chord of attic trusses). It's 22mm Caberfloor. Funnily enough I thought I'd read that somewhere but wasn't sure. I think if I did that I'd be forever paranoid about it dipping or hearing squeaks...

So it's not a big "no-no" to just cut the boards and butt them against each other over the joist then? The overall floor area is 17m x 5m so a lot of H noggins would be needed and I'm up against it in terms of time as well as energy and enthusiasm lol.

Thanks for the replies. Sadly over a length of 17 metres and 40 joists there's no groups that add up to exactly 2400mm so I can't shift along to find a decent place to even start. Presumably the H noggins don't need to be the full depth of the joist - would 4x2 be ok?

The floor joist centres are not consistent enough to land the joins of the 2400mm x 600mm T&G boards on joists (anywhere over a 17m span). So I'm debating whether to cut the boards to ensure all joins are on a joist (thus losing the T&G aspect) or to fit noggins and essentially additional floor joists between them, which will be both more time consuming and costly. Or can I just fit noggins centrally perpendicular to the joints (presumably this needs the T&G to be in pretty good order, sadly some have been stepped on and chipped a bit so I'd need to be selective)? The boards will all be glued and screwed so I guess square cut edges meeting over joists wouldn't be an issue. Any advice would be most welcome. Thanks all

Thanks. Funnily enough I've been looking at the lead substitute stuff. I may pop over to the roofing place this afternoon and have a look at it. Does it just lay onto the valley boards and then presumably membrane, tile battens etc over the top?

Hi all, I've used GRP valleys where three pitched roofs fall onto a section of flat roof and thought I'd use the same GRP valleys on the other side where the dormer pitch meets the main pitched roof but I'm struggling to find any decent info on how best to do it. The GRP valleys I have are the under-batten ones with the raised central fin and I'm using 30mm concrete pantiles (Marley Modern). The GRP valleys aren't exactly flexible so I'm not sure how I "poke" these out between tiles while remaining flat enough to place the tile over - having screwed it in place it has to bend in order to get it to go over the tile and it doesn't seem to like it too much so I wondered about ditching the GRP and doing a hidden one and mitre cutting the tiles to meet. Or is there a better solution? Below pics show my use of the valley around the flat roof and also a pic I found of a dormer using the same GRP valley that I've got - any advice would be most welcome. Thanks all.

Thanks. That was kind of what I was thinking, but thought I'd check in case the consensus was that it wasn't necessary. It's another of those things where you could save a few quid now but in the future you wish you'd spent the extra.

Sorry, should have been clearer - they're attic trusses designed to be usable rooms (bedrooms and bathrooms).

I've just installed new attic trusses at 400 centres and am looking at floor options. The "room" is 17 x 5m (to be divided up with stud walls). I've heard that 22mm is a must for 600 centres but for 400 centres I could use 18mm... I just wondered what people's thoughts are on 18mm vs 22mm? I've not priced up each yet but as they say in King's Cross, twenty quid's twenty quid... 😉

Nice - gotta love a Guzzi!! I keep looking on and off for an old 1000S (green/black or orange/black) and also a Daytona or 1100Sport. So many toys to try, yet so little time (and money!) I never really got the Harley thing. A friend had a FatBoy which I had a go on and admittedly it was good fun but at 300+kg I wouldn't want to drop it!!!

I'd like to span the full width so I can swap ends if I rearrange the room and I may hang other items from it too (obviously vastly lighter than the motorbike, possibly a couple of mountain bikes etc). I did wonder about a timber I-beam or glulam etc but I think then the cost would exceed the cost of steel perhaps?? It's an old 90's Ducati Superlight. I've not started it for around five years so it will need recommissioning - at some point I will sort it but at the moment the house is the priority sadly. It's currently in the lounge but her indoors said that's not a long term solution - strange! It's a Ducati - I think officially it's about 170kg but I thought I'd err on the side of caution. (Harley's are generally over 200kg). Thanks for the input guys.

Hi all, I'm looking to install a steel across the width of my garage with a view to suspending a motorbike from it (I've not ridden it for a few years and it's more just a display piece now). The span is 5.7m and I wondered what spec steel I would need. I wouldn't hang the bike centrally - it would be nearer one end of the steel near the wall. The bike weighs around 180kg. I know I probably ought to speak to an SE, but I thought I'd see if there was any general consensus here on what spec I should go for. I'm kind of looking for the smallest possible size really so it's a) not too intrusive and b) I've got a fighting chance of getting it in place. Any help would be much appreciated. Cheers

Evening all, Having built up to DPC all round, I'm now building up the floor layers within the rooms of the extension. I have a couple of soil pipes which will need to run partly through the hardcore layer and also through the concrete layer. Any advice on how I should do this would be greatly appreciated. I was thinking about sleeving the 110mm soil pipe inside a 160mm soil pipe (since I have a load of that) within the hardcore and concrete layers. Or should I shutter off the route of the pipe through the hardcore & concrete. Or should I just lay the pipes surrounded by pea shingle and backfill around it and then concrete over? The construction drawings show the layers as follows: 70mm screed 100mm insulation 25mm sand blinding 125mm concrete slab (with A252 mesh) 25mm sand blinding 150mm well compacted hardcore. Also, is it ok to connect the kitchen waste into a soil pipe running from a WC using a strap boss kit (this would be under floorboards)? I hope I've described things ok. Many thanks for any input.

So like this then? Looks good to me! Thanks all. Stay tuned for more noob questions!!

Thanks Radian and Temp, both look a better layout than my diagram. The only observation I have on Temp's layout would be that a 440 padstone would then sit directly on top of a 440 block (ie not staggered) - is it ok to do that? Cheers

Hopefully attached images will help describe it - as part of a rear extension there are two adjacent rooms each with sliding patio doors and between the doors is 1200mm wide wall (with padstones at the top to support steels above the patio doors). Construction is 440mm blocks. So, 440+440+300 (plus mortar joints) would be the 1200mm, but the next course would then leave a 70mm piece at the end (220+440+440+70 plus mortar joints = 1200mm). My question is, is it ok to have a 70mm piece at the end, or is there a better layout? Many thanks for any input!

Thanks Canski. I was thinking along the same sort of lines really, just thought I'd see if there was any reason not to. Cheers

For an extension using blocks, how low down the wall should I attach the wall starter kit? Should I start a few inches up from the footing so the first tie is at the first course (there will be about 2.5 blocks below ground level), or is it only required from say ground level, or even dpc and up...? And is a tie then needed at every course of blocks? Many thanks as usual.

Bungalow extension block requirement. The drawing states "Blockwork to be 100mm medium density (frost resistant below DPC). To provide a minimum mass per unit area (laid weight) of 120kg/m2. A mean compressive strength 3.5n/m2 and a thermal conductivity of 0.45w/mk." It will be a rendered finish. I was about to place the order for the blocks and spoke to the supplier's helpline to confirm suitability and it turns out that the ones I was going to order aren't suitable for 150mm above or below the ground level - so I'd need 2 courses of engineering bricks either side of the ground level. I'd rather use blocks all the way really - can anyone recommend a suitable block which I can use throughout? Many thanks

Thanks for the replies everyone! I have around 800-900mm from top of concrete to finished floor level. Is it ok to use cut blocks? So if I trim down some blocks to account for the change in level will it compromise the strength of the block?

My right hand man came down with the dreaded lurgy the night before I had three full readymix loads delivered for footings! So I had 36m3 to deal with on my own, which was, er, intense to say the least! Anyway, the upshot is that over the length of about 59 linear metres of footings there is a bit of a difference in levels at a few points. With something of a wry smile, the architect said it's not the worst he's seen, so that's encouraging... My question is - what are people's opinions / knowledge on the acceptable maximum thickness of the mortar bed when building from the footings with blocks? And I guess the same question regarding the mortar thicknesses of the next couple of courses or so. I think there'll be a little jiggery pokery needed and some coursing blocks and cuts (is it ok to cut blocks to suit height-wise?) to get me up to a nice level dpc. Any input and guidance is much appreciated!

Thanks everyone! It's quite clay-y (is that a word?!?) so as you say Conor, it'll all change once I start digging. The position of the new footings is all level ground so that's handy. I've already dug a fair bit by hand - I've exposed all of the original garage footings, so they now need breaking up with the pecker to get them gone ready for the new footings. Where I'm stepping up by 500mm as I get farther from the nearest tree, it would mean that the concrete would only be 200mm thick - having queried this with my SE this afternoon his reply was "Correct but you need minimum 450 concrete depth 1m below GL regardless". I understand this to mean any concrete that extends beyond 1 metre depth must be a minimum of 450mm from the top of the concrete.... ORRRR does this mean that it must extend 450mm below the 1m point, ie the bottom of the concrete will be at 1450mm and the top will be matching existing footings level at 600mm below GL, therefore thickness of concrete is 850mm....?? Sorry to sound daft but obviously I just want to meet the requirements.

The spec is 1600mm depth and 600mm width. Stepped up by 500mm when 1500mm further from tree location. What hasn't been clarified is where that depth is measured from (and, assuming the top level of the concrete matches existing foundation, would then tell me the thickness of concrete).

Sorry, I was meaning after I've dug the trenches and sent the digger back, I don't want to then hire it again to dig deeper if building control aren't happy. I guess I can try to get them out to inspect while the digger's still on site but then they'll need to come again when all trenches are dug...

Thanks Joe. My SE hasn't been specific with depth / thickness of concrete hence my question. I'm hiring a digger so don't want to do it all and then have building inspector say it's not deep enough and have to then re-hire the digger (and conversely I'd like to avoid going way too deep and thus costing myself more unnecessarily in excess concrete). Regarding the laying of blocks in the trench, I thought you had to start below ground level due to frost etc? And doesn't the concrete have to be to the same level as the existing building?