September 13, 20215 yr 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
September 13, 20215 yr 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.
September 13, 20215 yr Forgot to mention …. Don’t forget to puff the holes out. Dust is the scourge of resin anchoring systems
September 13, 20215 yr Author Ok Not used resin ones before ? Recommendations ? . Can I have bolts that are resin and anchor ??
September 13, 20215 yr 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, 20215 yr by markc
September 13, 20215 yr Author 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 ?
September 13, 20215 yr 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
September 13, 20215 yr @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, 20215 yr by markc
September 13, 20215 yr 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.
September 13, 20215 yr 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
September 13, 20215 yr Author 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
September 13, 20215 yr Author The washers / packers under each stringer won’t be visible when complete
September 13, 20215 yr Author 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, 20215 yr by pocster
September 13, 20215 yr 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.
September 13, 20215 yr Author 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 ?
September 13, 20215 yr Author 120mm m12 anchor bolts ordered ( found some new cheap ones on eBay - Fischer still ) . Steel square washers ordered also .
September 14, 20215 yr 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.
September 14, 20215 yr 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.
September 14, 20215 yr 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.
September 14, 20215 yr 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, 20215 yr by markc
September 14, 20215 yr 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, 20215 yr by Onoff
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