MortarThePoint Posted October 29, 2020 Share Posted October 29, 2020 Structural Engineer has specified 30x5mm straps and their c/c distance, but not their length. Any thoughts on what length to use for wall plate? Obviously above any openings they shouldn't be long enough to reach the opening ?. The top of wall plate is 525 above top of frame so I guess that means max. 500mm straps there. What do people recommend for panels? Other perhaps more daft questions: I presume the strap goes down the inside of the inner leaf rather than down the cavity Are the lengths generally stated as plus or including the bend? My inner leaf is 100mm. If the bent bit is 150mm should it be cut or not bother? Link to comment Share on other sites More sharing options...
nod Posted October 29, 2020 Share Posted October 29, 2020 1200 straps are fine for wall plate Go either side of openings 1500 Straps for trusses and floor joists 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted October 29, 2020 Share Posted October 29, 2020 1 hour ago, MortarThePoint said: ... My inner leaf is 100mm. If the bent bit is 150mm should it be cut or not bother? I wouldn't bother but, apart from laziness, can't tell you why I think that. Oh, I know, our chippie says if you don't need to cut something, don't. Very nice man, very very nice man. 1 Link to comment Share on other sites More sharing options...
Oz07 Posted October 29, 2020 Share Posted October 29, 2020 1.2 centres I thought it was usually no more than 2m. Usually you come down 4 blocks or so. 900/1200 straps Link to comment Share on other sites More sharing options...
joe90 Posted October 29, 2020 Share Posted October 29, 2020 Be on the safe side 1200mm. Link to comment Share on other sites More sharing options...
nod Posted October 29, 2020 Share Posted October 29, 2020 2 minutes ago, Oz07 said: 1.2 centres I thought it was usually no more than 2m. Usually you come down 4 blocks or so. 900/1200 straps I set mine at 1800 It worked in nicely either side of all the windows Link to comment Share on other sites More sharing options...
MortarThePoint Posted October 29, 2020 Author Share Posted October 29, 2020 1 hour ago, nod said: 1200 straps are fine for wall plate Go either side of openings 1500 Straps for trusses and floor joists Don't want to annoy the Structural Engineer so will try to observe the 1200 centres, but have a strap immediately either side of openings and if the opening is >1000mm have 500mm long strap(s) in middle. 3 minutes ago, Oz07 said: 1.2 centres I thought it was usually no more than 2m. Usually you come down 4 blocks or so. 900/1200 straps 1.2 is no more than 2 ? Link to comment Share on other sites More sharing options...
nod Posted October 29, 2020 Share Posted October 29, 2020 21 minutes ago, MortarThePoint said: Don't want to annoy the Structural Engineer so will try to observe the 1200 centres, but have a strap immediately either side of openings and if the opening is >1000mm have 500mm long strap(s) in middle. 1.2 is no more than 2 ? 1.8 ? Link to comment Share on other sites More sharing options...
Oz07 Posted October 29, 2020 Share Posted October 29, 2020 How is 1.2 no more than 2? On 12m of wall you would use 13 as opposed to 7 at 2m Link to comment Share on other sites More sharing options...
MortarThePoint Posted November 1, 2020 Author Share Posted November 1, 2020 A friend has used 7.5x50 ScrewFix EasyDrive concrete screws to fix his straps to the walls and I'd like to go that way as well: NHBC say: Fixings for straps should be: in accordance with the design, and the lowest fixing should be within 150mm of the bottom of the vertical strap of a material or finish which is compatible with the straps where into masonry, hardened 4mm x 75mm nails or 50mm long No 12 wood screws (into suitable plugs). What have others done? I'm inclined to think the concrete screw will be better than a woodscrew in a plug Link to comment Share on other sites More sharing options...
PeterW Posted November 1, 2020 Share Posted November 1, 2020 Better choice are these as they are pan head so sit better and also should fit through the holes in the straps without drilling. https://www.screwfix.com/p/easydrive-pan-concrete-screws-6-x-60mm-100-pack/9665r What sort of blocks have you got ..? Link to comment Share on other sites More sharing options...
MortarThePoint Posted November 1, 2020 Author Share Posted November 1, 2020 1 minute ago, PeterW said: Better choice are these as they are pan head so sit better and also should fit through the holes in the straps without drilling. https://www.screwfix.com/p/easydrive-pan-concrete-screws-6-x-60mm-100-pack/9665r What sort of blocks have you got ..? Thanks Peter. They are Plasmor 7.3N Fibolite blocks Link to comment Share on other sites More sharing options...
MortarThePoint Posted November 1, 2020 Author Share Posted November 1, 2020 On 29/10/2020 at 19:12, Oz07 said: How is 1.2 no more than 2? On 12m of wall you would use 13 as opposed to 7 at 2m 1.2m is less than 2m so meets the requirement (maximum of 2m centres). Yes it is more straps though Link to comment Share on other sites More sharing options...
MortarThePoint Posted November 1, 2020 Author Share Posted November 1, 2020 I saw this article which seems good: https://www.practicalarchitecture.com/blog/how-to-detail-a-wallplate They suggest "Wall plate shall be fixed to wall with Fischer SXRL10mm dia frame fixings 140mm long at max 1m ctrs in centre of wall plate, installed after mortar has set." Could be another place for a masonry screw since he Structural Engineer didn't specify the use of vertical screws through wall plate into masonry, but they seem a good idea. Not sure 75x100 is called for. I had intended to use C24 timber rather than C16 Link to comment Share on other sites More sharing options...
PeterW Posted November 1, 2020 Share Posted November 1, 2020 4x3 wall plates are for stiffness as well as build up so if that is spec then why change ..? I use concrete screws to hold down wall plates and 140mm are fine for that purpose. 1 Link to comment Share on other sites More sharing options...
MortarThePoint Posted November 1, 2020 Author Share Posted November 1, 2020 44 minutes ago, PeterW said: 4x3 wall plates are for stiffness as well as build up so if that is spec then why change ..? I use concrete screws to hold down wall plates and 140mm are fine for that purpose. Structural Engineer specified 100x50 wallplate, I was just commenting on the article. 140mm screws sound good. Do you use the same pan head screw type you suggested above, or do you use plugs? Link to comment Share on other sites More sharing options...
PeterW Posted November 1, 2020 Share Posted November 1, 2020 Just use countersunk 7.5 concrete screws as they are easy and don’t get in the way. 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted November 2, 2020 Share Posted November 2, 2020 16 hours ago, MortarThePoint said: ... What have others done? I'm inclined to think the concrete screw will be better than a woodscrew in a plug Yes, you are right, for us 7.5 concrete screws are perfect. @PeterW reminded me that they should be drilled over-length (10 mm or so) to take account of the dust that you simply cant extract. So for us ( straight into the ICF concrete ) that means a 6mm or maybe 6.5mm SDS hole , bored 110mm ( for a 100mm screw) thats rated 7.5. The grip is fantastic Link to comment Share on other sites More sharing options...
Dave Jones Posted November 2, 2020 Share Posted November 2, 2020 normally you will have breeze/thermolite blocks on the inner skin. Just drive a normal 50mmish wood screw straight in as will be dabbed over anyway. Link to comment Share on other sites More sharing options...
SimonD Posted November 2, 2020 Share Posted November 2, 2020 19 hours ago, MortarThePoint said: A friend has used 7.5x50 ScrewFix EasyDrive concrete screws to fix his straps to the walls and I'd like to go that way as well: NHBC say: Fixings for straps should be: in accordance with the design, and the lowest fixing should be within 150mm of the bottom of the vertical strap of a material or finish which is compatible with the straps where into masonry, hardened 4mm x 75mm nails or 50mm long No 12 wood screws (into suitable plugs). What have others done? I'm inclined to think the concrete screw will be better than a woodscrew in a plug If you're using Simpson Strong-Tie restraint straps, the data sheet says: 'Where straps are fixed to masonry, hardened nails Ø4mm x 75mm long or wood screws into plastic plugs Ø5.5 x50mm long should be used. The lowest fixing should be located within 150mm of the bottom of the vertical strap.' The data sheet also has all the recommended spacings and length. HTH Link to comment Share on other sites More sharing options...
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