Onoff Posted April 2, 2017 Author Share Posted April 2, 2017 (edited) I thought you really risked jacking if you don't pilot the board to CLEAR THE screw i.e the actual outside diameter of the threads. Just drilling a pilot the shank size still risks jacking IMHO. EDIT: I can alternate between stainless and Knauf screws if it keeps the peace! Edited April 2, 2017 by Onoff Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 2, 2017 Share Posted April 2, 2017 Yup. That's what I'm getting at. Clear the threads and its bingo bango. Link to comment Share on other sites More sharing options...
Onoff Posted April 2, 2017 Author Share Posted April 2, 2017 3 minutes ago, Nickfromwales said: Yup. That's what I'm getting at. Clear the threads and its bingo bango. I was taught woodwork at school when there was none of this new fangled self cutting stuff screw wise. Everything had a plain shank which required a clearance hole. Slotted was the norm and a Phillips head was considered exotic. Always wary of "needs no pilot". 1 Link to comment Share on other sites More sharing options...
Onoff Posted April 3, 2017 Author Share Posted April 3, 2017 The 39mm Knauf DIY Maxi Screws put in with the Makita and sunk just under flush into a test piece of Aquapanel - no pilot: 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 3, 2017 Share Posted April 3, 2017 Best to add that it's all to do with installer competence at the end of the day. Thats the 6th sense when one knows that a screw has gone in far enough and the board has firmed up against the timber. Many people assume that a tight screw is good enough, but it may still have to go a bit 'more' to send it fully home. PB screws are an extremely bad choice for this job as they're fully threaded, so are considerably more likely to promote jacking, but worse still they are very thin and extremely brittle so tend to snap very easily when more torque is applied than they're meant to accept. They're designed for soft plasterboard not rock hard backer boards . They'll snap even if you just accidentally drive them into a large knot so to use them for this application has, imo, been done out of laziness and / or penny-pinching. Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 3, 2017 Share Posted April 3, 2017 4 minutes ago, Onoff said: The 39mm Knauf DIY Maxi Screws put in with the Makita and sunk just under flush into a test piece of Aquapanel - no pilot: Seem to have set in pretty well. What's your gut feeling? The stuff is just too brittle for my liking so I'll be sticking with PB. Link to comment Share on other sites More sharing options...
Onoff Posted April 3, 2017 Author Share Posted April 3, 2017 (edited) These Knauf screws do seem rather "tough" tba. Go in with very little spoil generated as the ribs countersink the board. I just took the screws out and there was no "lift" of the board as it backed out. Hardly any breakout at the back and a clean hole bored with no pilot. Each screw has Aquapanel precisely engraved on the head and they are reassuringly expensive! Where the wc is going is just one Aquapanel where the red line is. Blue centre lines of where I can get fixings: Edited April 3, 2017 by Onoff Link to comment Share on other sites More sharing options...
Construction Channel Posted April 3, 2017 Share Posted April 3, 2017 has anyone tried them in hardi backer? I assumed it was similar stuff but looking at those pictures they look more like Wedi board?? Link to comment Share on other sites More sharing options...
jack Posted April 3, 2017 Share Posted April 3, 2017 Fermacell similarly recommends not using drywall screws. Guess what the same guys who did our bathrooms used on the Fermacell? Link to comment Share on other sites More sharing options...
Construction Channel Posted April 3, 2017 Share Posted April 3, 2017 14 minutes ago, jack said: Guess what the same guys who did our bathrooms used on the Fermacell? 50mm ring shanks?? 1 Link to comment Share on other sites More sharing options...
Onoff Posted April 3, 2017 Author Share Posted April 3, 2017 24 minutes ago, jack said: Fermacell similarly recommends not using drywall screws. Guess what the same guys who did our bathrooms used on the Fermacell? Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 3, 2017 Share Posted April 3, 2017 2 hours ago, jack said: Fermacell similarly recommends not using drywall screws. Guess what the same guys who did our bathrooms used on the Fermacell? Still better than the risks associated with buying a taylor wimpey home, even if they do now 'boast' "quality insulation" and "water saving boilers". Wtf . @jack, are these issues currently only in the bathrooms? Edit : oops, wrong thread to ask. I'll just nip next door to jacks house Link to comment Share on other sites More sharing options...
jack Posted April 4, 2017 Share Posted April 4, 2017 10 hours ago, Nickfromwales said: @jack, are these issues currently only in the bathrooms? Edit : oops, wrong thread to ask. I'll just nip next door to jacks house @Nickfromwales, you're not the only one to have confused the two threads I think! Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 4, 2017 Share Posted April 4, 2017 12 minutes ago, jack said: @Nickfromwales, you're not the only one to have confused the two threads I think! It's Clive's fault for selfishly worrying about his own bathroom Link to comment Share on other sites More sharing options...
jack Posted April 4, 2017 Share Posted April 4, 2017 Link to comment Share on other sites More sharing options...
jack Posted April 4, 2017 Share Posted April 4, 2017 I should add, anyone whose thread about his bathroom extends to 27 pages isn't really in a position to complain about occasional off-topic detours! 1 Link to comment Share on other sites More sharing options...
Onoff Posted April 4, 2017 Author Share Posted April 4, 2017 That's a very...bouncy...video... Anyway, back on track: Despite my best efforts some of the timber faces that the Aquapanel will go on are a little low. I can slip in a (yellow) 1mm shim here and there. I could set the plane and glue 1mm thick strips of timber on to get a continuous pack. I'm thinking it'd be better just to put the board on with lines of Sikaflex on the timber but don't screw to the low areas until the Sikaflex has gone off. That way it will have dried as a continuous pack? Link to comment Share on other sites More sharing options...
Onoff Posted April 4, 2017 Author Share Posted April 4, 2017 1 minute ago, jack said: I should add, anyone whose thread about his bathroom extends to 27 pages isn't really in a position to complain about occasional off-topic detours! Does that include pages on the old forum? I'm feeling your pain btw with all your grief. People's definitions of "quality" vary so much and I'm sure to many trades it's just a job. I'm guessing though you've at least a nice warm, draught free shell within where you can fix it all! Link to comment Share on other sites More sharing options...
PeterW Posted April 4, 2017 Share Posted April 4, 2017 6 minutes ago, Onoff said: I could set the plane and glue 1mm thick strips of timber on to get a continuous pack. I'm thinking it'd be better just to put the board on with lines of Sikaflex on the timber but don't screw to the low areas until the Sikaflex has gone off. That way it will have dried as a continuous pack? Seriously.... Sikaflex, screw it on and be done with it ! You cannot see a 1mm deflection in a backing board, from memory they are made to 0.5mm tolerance anyway so it may not be 1mm.... 2 Link to comment Share on other sites More sharing options...
jack Posted April 4, 2017 Share Posted April 4, 2017 11 minutes ago, Onoff said: I'm feeling your pain btw with all your grief. People's definitions of "quality" vary so much and I'm sure to many trades it's just a job. I'm guessing though you've at least a nice warm, draught free shell within where you can fix it all! Yes, definitely warm and draft free now all the roof leaks have been fixed! #firstworldproblems Link to comment Share on other sites More sharing options...
Onoff Posted April 4, 2017 Author Share Posted April 4, 2017 (edited) Next question..... I need, very shortly to drill a hole in the top (?) of the cistern and run a pipe up into the loft. This, for an "odour" take off pipe alluded to elsewhere. Easiest for me would be a bit of 20mm flexible conduit and an M20 stuffing gland siliconed in. Sound about right? Edited April 4, 2017 by Onoff Link to comment Share on other sites More sharing options...
Onoff Posted April 4, 2017 Author Share Posted April 4, 2017 2 minutes ago, jack said: #firstworldproblems Oh yeah, and my dormer leaks in all 4 corners and elsewhere. Swap you? Link to comment Share on other sites More sharing options...
jack Posted April 4, 2017 Share Posted April 4, 2017 1 minute ago, Onoff said: Swap you? Finish the bathroom first and we can talk! Link to comment Share on other sites More sharing options...
Onoff Posted April 4, 2017 Author Share Posted April 4, 2017 31 minutes ago, jack said: Finish the bathroom first and we can talk! I'll throw in the wife's recipe for lemon ice cream! Negotiations #Not The Nine O'clock News style! Link to comment Share on other sites More sharing options...
jack Posted April 4, 2017 Share Posted April 4, 2017 17 minutes ago, Onoff said: Negotiations #Not The Nine O'clock News style! Throw in Gibraltar and it's a deal! 1 Link to comment Share on other sites More sharing options...
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