MortarThePoint Posted October 3, 2020 Share Posted October 3, 2020 We've just installed some steel beams (UC 203x203x86). One padstone looks to be a bit out of level and across the 400mm opens up a gap of about 3 mm. Is this a worry? If so what should be done to fix it? For reference, the bottom flange of the beam is 20.5mm in height. The padstones are large and heavy (660x190x215, about 65kg) so getting them perfectly level would always be a challenge. Link to comment Share on other sites More sharing options...
PeterW Posted October 3, 2020 Share Posted October 3, 2020 1:1 cement and sand thin mortar bed will sort that. You won’t split slate fine enough. Worth checking the other end too, is it absolutely level..? Depending on the length of the beam, it may be that it’s deflecting enough to kick the end up slightly. Are they being bolted down at all..? 1 Link to comment Share on other sites More sharing options...
PeterW Posted October 3, 2020 Share Posted October 3, 2020 Just a query - who specced the beam / padstones..? You have a 190mm padstone with a 203mm beam so an overhang..? Would have been better going to a 254 x 146 and getting it to properly sit on. Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 (edited) 23 minutes ago, PeterW said: 1:1 cement and sand thin mortar bed will sort that. You won’t split slate fine enough. Worth checking the other end too, is it absolutely level..? Depending on the length of the beam, it may be that it’s deflecting enough to kick the end up slightly. Are they being bolted down at all..? Thanks PeterW. The beam is 4m clear span and currently not loaded other than self weight. Another beam of similar length has much less of a gap <=1mm. I had wondered about using stainless steel shims. They're not getting bolted down. I had asked the Structural Engineer a couple of weeks ago about that and he said that thermal expansion could cause masonry cracking so he wasn't a fan. The drawing says "END OF BEAM T BE FULLY ENCASED IN MASONRY, FILLING ALL VOIDS WITH RAMMED DRY PACK MORTAR". Is this the sort of void that's referring to? Edited October 3, 2020 by MortarThePoint Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 This beam looks spot on for level. Haven't check the other ones but expect OK. Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 (edited) 12 minutes ago, PeterW said: Just a query - who specced the beam / padstones..? You have a 190mm padstone with a 203mm beam so an overhang..? Would have been better going to a 254 x 146 and getting it to properly sit on. Structural Engineer designed it as a change from a different original design. The beam is ever so slighly wider than the padstones. The padstones are actually a 200mm wide, not ordered as such but that's what they ended up as. The SE was happy with the overhang and a 254 x 146 has less out of plane strength whilst also being deeper which was undesirable. Edited October 3, 2020 by MortarThePoint Link to comment Share on other sites More sharing options...
nod Posted October 3, 2020 Share Posted October 3, 2020 Your steel is to wide or padstone to narrow Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 Just now, nod said: Your steel is to wide or padstone to narrow The widths are fine, it's the level and the gap that opens up that I'm wondering about. Link to comment Share on other sites More sharing options...
PeterW Posted October 3, 2020 Share Posted October 3, 2020 45 minutes ago, MortarThePoint said: The drawing says "END OF BEAM T BE FULLY ENCASED IN MASONRY, FILLING ALL VOIDS WITH RAMMED DRY PACK MORTAR". Is this the sort of void that's referring to? so ... 41 minutes ago, MortarThePoint said: The SE was happy with the overhang and a 254 x 146 has less out of plane strength whilst also being deeper which was undesirable. ...? So your spec says that it should be fully encased, but your beam overhangs the padstone...? You can’t do both ..! The spec will be for fire protection - that beam will also need two layers of plasterboard to encase it. And yes, you can dry pack that lot but it will be much easier with a 1:1 semi dry bed mix. Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 48 minutes ago, PeterW said: And yes, you can dry pack that lot but it will be much easier with a 1:1 semi dry bed mix. The challenge is a bed mix involves lifting one end of a 400kg beam. I could use an acrow I suppose. Link to comment Share on other sites More sharing options...
Mr Punter Posted October 3, 2020 Share Posted October 3, 2020 If you are keen to increase the bearing you could use some metal shims or some runny structural grout. Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 56 minutes ago, Mr Punter said: If you are keen to increase the bearing you could use some metal shims or some runny structural grout. Runny structural grout sounds interesting. What sort of mix is that or is there a particular product I should look out for? Link to comment Share on other sites More sharing options...
Onoff Posted October 3, 2020 Share Posted October 3, 2020 2 minutes ago, MortarThePoint said: Runny structural grout sounds interesting. What sort of mix is that or is there a particular product I should look out for? Weber Five Star Grout we use at work for packing clearance holes through structural slabs. Link to comment Share on other sites More sharing options...
PeterW Posted October 3, 2020 Share Posted October 3, 2020 3 minutes ago, MortarThePoint said: Runny structural grout sounds interesting. What sort of mix is that or is there a particular product I should look out for? Sika 111 is the one I use - you would not need much, just duct tape round the edges and pour it in. Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 3, 2020 Author Share Posted October 3, 2020 3 minutes ago, Onoff said: Weber Five Star Grout we use at work for packing clearance holes through structural slabs. Just now, PeterW said: Sika 111 is the one I use - you would not need much, just duct tape round the edges and pour it in. Thanks, these look great. They look to develop a strength of 40MPa which is 40N/mm2 so close to C50 cement of the padstone and should be runny enough to flow or get pushed in. Wonder if I can get less than a 25kg bag as I'll need less than 1kg. Link to comment Share on other sites More sharing options...
willbish Posted October 3, 2020 Share Posted October 3, 2020 If your steel beam is level and your padstone is slightly on the pi$$ you aren't going to be able to pour a runny grout mix up hill. Wedge a few steel shims in there Link to comment Share on other sites More sharing options...
sean1933 Posted February 22, 2021 Share Posted February 22, 2021 On 03/10/2020 at 18:48, PeterW said: Sika 111 is the one I use - you would not need much, just duct tape round the edges and pour it in. Sorry for thread hijack but could really do with some help with this exact product if possible. Mixed and poured under steel post thermal break pads last night (literally midnight!) Which are sitting on levelling nuts so approx 30-35mm thick. Expected it to be rock solid this morning but it was still soft. I've now taken formwork off and cut back with trowel, it is drying slowly but 16hrs later it still seems wet but grainy and brittle. In your experience of the product, is this right? I didn't expect it to take so long to go off but curing time doesn't state temperature and I know it can impact it a lot. Worried I'm going to have to smash it all out and start again, need to be prepared as its now impeding the brickys progress. Thanks in advance! Link to comment Share on other sites More sharing options...
Dave Jones Posted February 22, 2021 Share Posted February 22, 2021 brickies normally pack out any bows with some slate. Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 22, 2021 Share Posted February 22, 2021 1 hour ago, sean1933 said: Sorry for thread hijack but could really do with some help with this exact product if possible. Mixed and poured under steel post thermal break pads last night (literally midnight!) Which are sitting on levelling nuts so approx 30-35mm thick. Expected it to be rock solid this morning but it was still soft. I've now taken formwork off and cut back with trowel, it is drying slowly but 16hrs later it still seems wet but grainy and brittle. In your experience of the product, is this right? I didn't expect it to take so long to go off but curing time doesn't state temperature and I know it can impact it a lot. Worried I'm going to have to smash it all out and start again, need to be prepared as its now impeding the brickys progress. Thanks in advance! Did you use the correct amount of water ? What was the temperature when poured and overnight, it should be 5 degrees and not dropping whilst curing. The stuff i used set very hard overnight, but was only 10mm thick. Link to comment Share on other sites More sharing options...
MortarThePoint Posted February 23, 2021 Author Share Posted February 23, 2021 Was it quite a dry pack mix you used? Link to comment Share on other sites More sharing options...
sean1933 Posted February 23, 2021 Share Posted February 23, 2021 Thanks for the replies alll. Turns out I was worrying about nothing - temperature was 7 degrees @ the pad and wasn't particularly well ventilated which I guess made it take a while to set. Annoyingly the sika instructions are silent on what temp the cure time is, but from looking at the same product from Weber it seems normal stated times are at 20deg, the 5deg times are 3 times as long. Thankfully gone off like a rock now. 1 Link to comment Share on other sites More sharing options...
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