Pocster Posted September 13, 2021 Share Posted September 13, 2021 Got to attempt to fix my external metal staircase to the concrete wall . Been told m12 anchor bolts . Any type / brand recommendations? Also the stairs will need packing under the stringers . What should I use for external packing ? . Assume plastic window packers aren’t really going to do it . Packing maybe as much as 30mm Link to comment Share on other sites More sharing options...
Mr Punter Posted September 13, 2021 Share Posted September 13, 2021 I prefer resin fixings. Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 Pack with washers or steel plate and grout after to tidy up. resin anchors make life much easier than sleeve anchors. put the piece in place and mark through the holes. drill holes (generally 2mm oversize than threaded rod diameter). put piece back in place. Squeeze resin into hole and spin the threaded rod in with reverse rotation … this forces the resin inwards and fills all cavities. leave to set then tighten nuts. this is much easier than trying to set the rods and then put the piece into place. Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 Forgot to mention …. Don’t forget to puff the holes out. Dust is the scourge of resin anchoring systems Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 Ok Not used resin ones before ? Recommendations ? . Can I have bolts that are resin and anchor ?? Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 (edited) 17 minutes ago, pocster said: Ok Not used resin ones before ? Recommendations ? . Can I have bolts that are resin and anchor ?? If you want a bolt head then you are into sleeve anchors. place piece, drill hole same diameter as the sleeve, puff dust out, back bolt out as far as is practice, insert into hole and tighten. https://www.screwfix.com/p/fischer-fsa-sleeve-anchors-silver-12-x-81mm-m10-20-pack/68793 Edited September 13, 2021 by markc 1 Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 Or you could use masonry screws. They work well and have bolt head Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 3 minutes ago, markc said: If you want a bolt head then you are into sleeve anchors. place piece, drill hole same diameter as the sleeve, puff dust out, back bolt out as far as is practice, insert into hole and tighten. https://www.screwfix.com/p/fischer-fsa-sleeve-anchors-silver-12-x-81mm-m10-20-pack/68793 More comfortable with those . The stringers heavy and awkward . So want to place it - drill holes without moving it away I.e drill in situ . Assume this is ok still ? Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 Just now, pocster said: More comfortable with those . The stringers heavy and awkward . So want to place it - drill holes without moving it away I.e drill in situ . Assume this is ok still ? Yes, that anchor will work well and bolt head is neat 1 Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 (edited) @pocster if the heads will not be visible then through anchors are easier but you have a nut visible like this https://www.screwfix.com/p/fischer-fxa-throughbolts-m12-x-116mm-20-pack/48990 Edited September 13, 2021 by markc Link to comment Share on other sites More sharing options...
saveasteading Posted September 13, 2021 Share Posted September 13, 2021 All agreed as per MarkC. A stair is a fairly stable and static thing, so very little pull-out on the fixings. If the Engineer says M12 then M12. But you can get M12 into plastic plugs so is very easy. For shims, the easy and cheap source is fence washers, big ones. screwfix as this https://www.screwfix.com/p/easyfix-steel-square-washers-m12-x-4mm-50-pack/452ft If you go to a merchant they will try to charge £50 for a bag of a hundred but come down to £15 or so on demand, so get a price from the rep first. Steel shims are otherwise stupidly expensive, so a few hundred steel sheds are on the washers...BUT then fully grouted with dry mix afterwards. Shims (and washers) often have bends and sticky-out bits and don't pack tightly, so also give them a bash to flatten out. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted September 13, 2021 Share Posted September 13, 2021 For certainty of fixing I would choose a combined screw and plug, like these. BUT I would use Fischer or other big brand....diall own brand are very variable I have found, but I couldn't quickly find Fischer bigger than 10mm. They exist and I'm sure you will find them if interested. https://www.diy.com/departments/diall-universal-nylon-steel-wall-plug-l-60mm-dia-12mm-pack-of-20/1584932_BQ.prd 1 Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 28 minutes ago, markc said: @pocster if the heads will not be visible then through anchors are easier but you have a nut visible like this https://www.screwfix.com/p/fischer-fxa-throughbolts-m12-x-116mm-20-pack/48990 Head visible under the staircase - not worried about that Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 The washers / packers under each stringer won’t be visible when complete Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 (edited) What is surprising is the lack of fixing holes along the stringer . Though not fully unpacked I can see just 2 at the top . Nothing along it , then 2 for the base plate to the floor . Would of been happier with a few holes along the stringer ? Especially as when I pick it up it bends …. Edited September 13, 2021 by pocster Link to comment Share on other sites More sharing options...
markc Posted September 13, 2021 Share Posted September 13, 2021 It’s amazing how floppy steel stairs are until they are fully bolted up. 1 Link to comment Share on other sites More sharing options...
joe90 Posted September 13, 2021 Share Posted September 13, 2021 Drill more holes if you want but there is not much load on it as it’s resting on the floor at the base and wall at the top and will be stiffer once all bolted up. ? (I prefer resin bolts, stainless threaded rod from screwfix cut to length, nuts, washers, resin) but as said above the hole must be dust free or the resin won’t grip the concrete. 1 Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 9 minutes ago, markc said: It’s amazing how floppy steel stairs are until they are fully bolted up. I assumed it would be ridged like a steel lintel . Bends like a boy ! . Hope it doesn’t snap ? The wall lip fixing has to go up first . For reason unknown it doesn’t support the stringer . That would of been really helpful ! But I’ll use some acro’s to position the stringer as I have to lower it into the pit . My internal doors have just turned up - so I can avoid this task for now ? Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 Link to comment Share on other sites More sharing options...
Pocster Posted September 13, 2021 Author Share Posted September 13, 2021 120mm m12 anchor bolts ordered ( found some new cheap ones on eBay - Fischer still ) . Steel square washers ordered also . Link to comment Share on other sites More sharing options...
Conor Posted September 14, 2021 Share Posted September 14, 2021 14 hours ago, pocster said: 120mm m12 anchor bolts ordered ( found some new cheap ones on eBay - Fischer still ) . Steel square washers ordered also . Stainless steel I hope, or at least galvanized. Link to comment Share on other sites More sharing options...
Onoff Posted September 14, 2021 Share Posted September 14, 2021 1 hour ago, Conor said: Stainless steel I hope, or at least galvanized. Yep, stainless steel everything or over time they'll all rust and blow the concrete aside from leaching rust down the staircase. He has been warned. 1 Link to comment Share on other sites More sharing options...
Onoff Posted September 14, 2021 Share Posted September 14, 2021 18 hours ago, pocster said: Doesn't the above "hook" over the concrete lip at the top? Are there any holes so you can fix in place? The stringer tops then connect to those slots don't they? What's the finish? If powder coat over plain steel without the steel being zinc flame sprayed or galvanised then that's not the best finish for longevity. Link to comment Share on other sites More sharing options...
markc Posted September 14, 2021 Share Posted September 14, 2021 (edited) Looks like a fairly standard top lip. These usually get fixed vertically after lining and levelling. and powder coat only will chip and peel off, I would have had it galv first. Edited September 14, 2021 by markc Link to comment Share on other sites More sharing options...
Onoff Posted September 14, 2021 Share Posted September 14, 2021 (edited) 24 minutes ago, markc said: Looks like a fairly standard top lip. These usually get fixed vertically after lining and levelling. and powder coat only will chip and peel off, I would have had it galv first. With the top lip I was getting at there don't appear to be any pre drilled holes for fixing to the lip. If you drill anything powder coated you'll break the skin and water will get underneath. I've seen it so many times, PPC just lifting in sheets and rusty steel underneath. If you do have to drill extra holes @pocster then you need to clean the steel where you've drilled and touch up the coating. They may have given you a touch up pot? Tbh I'd pack round the hole with grease and just wipe off when nutted up. For all other fixings I'd be smearing the threads with aluminium based anti seize paste and dropping the torque settings a tad. Edited September 14, 2021 by Onoff 1 Link to comment Share on other sites More sharing options...
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