Adsibob Posted July 20, 2021 Share Posted July 20, 2021 The aperture for the sliding door we have ordered is 8mm higher than the sliding door manufacturer agreed with us when we ordered the sliding door. The aperture has been specified to be 20mm wider and 20mm taller than the door unit itself, effectively allowing a 10mm border all the way around for the compriband and fitting. 8mm doesn't sound like a lot, but if our door is 8mm lower than specified we won't have a flush threshold and instead will have an 8mm deep gap in the floor. So I asked the builder to build up the 8mm with something waterproof and solid. I suggested cement board. He said I'm fussing over nothing and the door company can sort this out when they fit the doors later this week and that 8mm is "within tolerances" and that otherwise they would struggle to get the door in. This last point must surely be wrong because presumably the door company has specified the size of the aperture knowing full well that they need to get the door into it. Actual door size is 4280 wide by 2352 high. I'm not worried about deflection because engineer has specified a solid beam above the opening and there is hardly any weight on the beam anyway. Am i fussing about nothing, or is the builder right? I tried calling the door company but can't get through. Link to comment Share on other sites More sharing options...
markc Posted July 20, 2021 Share Posted July 20, 2021 dont worry about it, im sure the door fitters will thank you for the extra packing room and give some wiggle room to get everything spot on. Link to comment Share on other sites More sharing options...
markc Posted July 20, 2021 Share Posted July 20, 2021 Just re reading your post - if the opening is 8mm higher than specified, how can the door end up 8mm lower?? Link to comment Share on other sites More sharing options...
Adsibob Posted July 20, 2021 Author Share Posted July 20, 2021 Sorry, i mean the height of the aperture is 8mm too much. The bottom of the opening needs to be 8mm higher than where it is. So if they just installed the door without correcting this, the door would be 8mm too low. Link to comment Share on other sites More sharing options...
Russell griffiths Posted July 20, 2021 Share Posted July 20, 2021 You do worry about some little things, chill out Rodney. I bet you any money you like the bottom brick/ concrete or whatever is not level, the fitters will put the door up on packers to get it level. You just need to mark the exact height you want it and tell them to lift it to that height. TBH your opening is not big enough, should be more clearance above to allow for deflection. Link to comment Share on other sites More sharing options...
Adsibob Posted July 20, 2021 Author Share Posted July 20, 2021 Thanks. You are right @Russell griffiths that i often worry too much. This building project has brought this character flaw into sharp focus! As a layman, it's difficult to know when 8mm matters and when it doesn't. E.g. relative to the 10mm space around the frame, 8mm is 80% out, whereas relative to the overall aperture 8mm is pretty tiny. But I guess they will work it out. The way I left it with the builder is: you will be here when they install the door and I won't, you know the level of the finished floor level and so you better make sure they can achieve this notwithstanding this 8mm discrepancy. So it's on him. Link to comment Share on other sites More sharing options...
Adsibob Posted July 20, 2021 Author Share Posted July 20, 2021 Door company came back to me. They said they can work with it being up to 4mm out, but more than that is “not great”. They suggest adding a 6mm thick cement board. Very similar to what I suggested! Back to speak to the builder! Link to comment Share on other sites More sharing options...
markc Posted July 20, 2021 Share Posted July 20, 2021 5 minutes ago, Adsibob said: Door company came back to me. They said they can work with it being up to 4mm out, but more than that is “not great”. They suggest adding a 6mm thick cement board. Very similar to what I suggested! Back to speak to the builder! Typical response, i wouldn't have said anything to them and the fitters would have just got on and done it. Good chance the door will not be the right size and if you then mention it you will likely get a "10mm either way makes no difference" Link to comment Share on other sites More sharing options...
Mr Punter Posted July 20, 2021 Share Posted July 20, 2021 I have never heard of such a tight tolerance. Why the hell would you want to add cement board? Just check that the threshold is completely level, fit the door and fill the gap at the top with plasterboard / mastic or whatever. Link to comment Share on other sites More sharing options...
Adsibob Posted July 20, 2021 Author Share Posted July 20, 2021 19 minutes ago, Mr Punter said: I have never heard of such a tight tolerance. Why the hell would you want to add cement board? Just check that the threshold is completely level, fit the door and fill the gap at the top with plasterboard / mastic or whatever. Well if we do that, we will have an 8mm deep divot rather than a flush threshold. There are three tracks for this sliding door, so it would be quite a wide divot. Link to comment Share on other sites More sharing options...
ProDave Posted July 20, 2021 Share Posted July 20, 2021 As I understand it , for a "level threshold" you are allowed a 15mm step. What I am reading is you will have an 8mm step down followed immediately by an 8mm step up. I don't see an issue with level access regs, but what stops it filling with water? Link to comment Share on other sites More sharing options...
Temp Posted July 20, 2021 Share Posted July 20, 2021 (edited) 2 hours ago, Adsibob said: Sorry, i mean the height of the aperture is 8mm too much. The bottom of the opening needs to be 8mm higher than where it is. So if they just installed the door without correcting this, the door would be 8mm too low. That still doesn't make a lot of sense to me. If the bottom track will be too low in relation to the finished floor level then I would make sure there is some 8mm packing/cement board available and tell them to use it. But I don't get the issue with the height of the opening. Are you saying that if they use 8mm packing at the bottom then the door won't fit in the opening because the lintel is too low? If yes then you have a problem. If no then more packing at the top. Edited July 20, 2021 by Temp Link to comment Share on other sites More sharing options...
Adsibob Posted July 20, 2021 Author Share Posted July 20, 2021 2 hours ago, Temp said: But I don't get the issue with the height of the opening. Are you saying that if they use 8mm packing at the bottom then the door won't fit in the opening because the lintel is too low? If yes then you have a problem. If no then more packing at the top. I don’t understand the confusion. Builder was instructed to build an opening that is 2372mm in height, from the bottom of the opening to the top. The bottom was to coincide with a level which was 170mm above the top of the slab. Builder has constructed an opening that is 2380mm in height and only 162mm above the slab. So by packing out the bottom of the opening with some cement board - which is what I asked him to do this morning - he would fix the issue. Simples. Builder has a complex personality issue which sometimes gets in the way of things. Complex. 1 Link to comment Share on other sites More sharing options...
PeterW Posted July 20, 2021 Share Posted July 20, 2021 2372mm doesn’t work any sort of unit though - 2380mm is 28 bricks high Link to comment Share on other sites More sharing options...
Temp Posted July 20, 2021 Share Posted July 20, 2021 1 hour ago, Adsibob said: I don’t understand the confusion. Builder was instructed to build an opening that is 2372mm in height, from the bottom of the opening to the top. The bottom was to coincide with a level which was 170mm above the top of the slab. Builder has constructed an opening that is 2380mm in height and only 162mm above the slab. So by packing out the bottom of the opening with some cement board - which is what I asked him to do this morning - he would fix the issue. Simples. Builder has a complex personality issue which sometimes gets in the way of things. Complex. Yes that clearer. Dealing with people is the hardest thing about self building. Link to comment Share on other sites More sharing options...
Adsibob Posted July 20, 2021 Author Share Posted July 20, 2021 1 hour ago, PeterW said: 2372mm doesn’t work any sort of unit though - 2380mm is 28 bricks high You are making the same mistake I made, which is to assume the bricklayer lays rows of bricks which were identical in height. I haven’t got the link to hand, but there is a video on a thread here of my rear elevation which shows the brickwork, and somebody commented that they were really impressed with it. It really is a thing of beauty. But three amount of mortar between each row is not identical. Anyway, it doesn’t really matter because the brickwork was finished before the door company attended to do the survey. At the point the aperture was measured and some changes were required, and he has only partially done the change, which is what has reported in the 8mm discrepancy. i agree with @Temp’s observation. Link to comment Share on other sites More sharing options...
Temp Posted July 20, 2021 Share Posted July 20, 2021 Now I understand what he's built I agree with both you and the builder. It's close enough. Just make sure the fitters use packing. We had to raise a window or two. Link to comment Share on other sites More sharing options...
dpmiller Posted July 21, 2021 Share Posted July 21, 2021 10 hours ago, Adsibob said: the brickwork was finished before the door company attended to do the survey in which case the door supplier already had the opportunity to correctly measure surely? Link to comment Share on other sites More sharing options...
markc Posted July 21, 2021 Share Posted July 21, 2021 13 minutes ago, dpmiller said: in which case the door supplier already had the opportunity to correctly measure surely? good point, i missed that Link to comment Share on other sites More sharing options...
ProDave Posted July 21, 2021 Share Posted July 21, 2021 If this is a wide sliding door, I would want at least 8mm spare clearance to allow for sag in any lintel above the door. Link to comment Share on other sites More sharing options...
Adsibob Posted July 21, 2021 Author Share Posted July 21, 2021 On 20/07/2021 at 17:07, ProDave said: I don't see an issue with level access regs, but what stops it filling with water? A slot drain. Link to comment Share on other sites More sharing options...
Adsibob Posted July 22, 2021 Author Share Posted July 22, 2021 Update: the builder has finally fixed it. Doors going in today, hopefully the 8mm of concrete will have set in time as it couldn’t have been poured more than 40 hours ago. Link to comment Share on other sites More sharing options...
Makeitstop Posted July 25, 2021 Share Posted July 25, 2021 How did your installation go Adsibob? Link to comment Share on other sites More sharing options...
Adsibob Posted July 25, 2021 Author Share Posted July 25, 2021 29 minutes ago, Makeitstop said: How did your installation go Adsibob? Not great to be honest. Door company called me from site about 30 min after arriving to say aperture was too short. Builder then threw his toys out the pram saying “I told you we shouldn’t have raised the floor under the opening”. Builder’s foreman then measured the door and spotted it was 4mm higher than specified by the door company’s own surveyor as confirmed in drawings. Builder agrees to shave off some of the extra cement he had put down. We had asked him to put down 8mm. For reasons unknown to me, he had put down about 18mm (wtf?!?). Door company is then apparently happy and installs the door. I send architect to inspect. He calls me up and says “I don’t wish to alarm you, but the gap above the door/below the steel is only 3mm to 4mm and SE specified 8mm max deflection.” Lots of swearing and shouting. Lots. i tell door company they need to take the door out and reinstall it 4mm lower. They say architect is wrong and there is 8mm of space. Architect then measures again and discovers some “concealed space”. Foreman and architect get laser level out to measure current deflection (about 75% of the load on the roof has been on for a few months already) of the beam. turns out the beam has only deflected by “just less than a mm” and that taking into account the “concealed space” whatever that is, there is 6.5mm of space at one end, about 7mm of space in the middle and about 8.5 or 9mm at the other end. The reason for this is that the steel isn’t perfectly level. Architect speaks to SE to ask him what he thinks. He asks if the door is top hung or bottom hung. Architect confirms it bottom. Engineer says it should be fine and that there isn’t much load on that beam anyway and 8mm would be the absolute limit and only in extreme conditions like 20cm of snowfall on the roof. I’m really not happy. This is a really expensive door (£11k including installation) we still have 26 square metres of seedum to lay on the roof. It’s maximum weight when fully saturated with water is 55kg per m2. There are also a couple of skylights still to go in which will add a bit of weight. In total, close to 2 tonnes when seedum is fully saturated. Architect points out that because of the loading, not much of that extra weight will bear on the beam. He is right about that, but it still freaks me out. He also says that as most of the weight has already been on it for a few months, I can take comfort from the fact that there is only “at most, 1mm of current deflection at the middle”. All extremely stressful and completely avoidable had everyone just done as asked and agreed on the drawings. Link to comment Share on other sites More sharing options...
Oz07 Posted July 25, 2021 Share Posted July 25, 2021 My god what an interesting tale. Builder will love recounting that down the pub. Be interesting to see what tolerance your 11k door company work to. I can appreciate a brickie getting an 8ft opening quarter of an inch too high, especially if rsj out of level. For a door company to survey after aperture is built, tell you the hole is wrong size then still make door 4mm too big I think it's their problem! Bet they wouldn't want to replace £££ Link to comment Share on other sites More sharing options...
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