nod Posted June 13, 2023 Share Posted June 13, 2023 Most of our commercial jobs won’t allow us to use anything other than bg metal It is heavier duty A good saving on MF is not to use deep Chanel If there are no deflection heads There’s no need I never use deep Chanel on houses 1 Link to comment Share on other sites More sharing options...
Chanmenie Posted June 13, 2023 Share Posted June 13, 2023 5 hours ago, nod said: Most of our commercial jobs won’t allow us to use anything other than bg metal It is heavier duty A good saving on MF is not to use deep Chanel If there are no deflection heads There’s no need I never use deep Chanel on houses Hi @nod when is a deflection head needed. My chalet bungalow will have attic trusses with a clear 9m span so there will be deflection, however I will have non load bearing block walls below which can reduce some of the deflection but not take the load of the trusses, so should I have a deflection head ? Link to comment Share on other sites More sharing options...
nod Posted June 13, 2023 Share Posted June 13, 2023 It tends to be mainly commercial builds No need on a private home Link to comment Share on other sites More sharing options...
saveasteading Posted June 13, 2023 Share Posted June 13, 2023 So the manual probably says something like 2mm deflection which is approximately zero. That will only occur with 2m of snow on the roof, and it won't collapse even then. Link to comment Share on other sites More sharing options...
nod Posted June 13, 2023 Share Posted June 13, 2023 20 minutes ago, saveasteading said: So the manual probably says something like 2mm deflection which is approximately zero. That will only occur with 2m of snow on the roof, and it won't collapse even then. Not really I’ve recently put 300 mil deep head track in a building where 100 mil of deflection is anticipated Normal would be to allow 40 mil Offices factories Multi floor TF Never on houses Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 afternoon all. I'm now thinking about a different dropped ceiling requirement. in the kids rooms we want to have the LED strips in a dropped ceiling look. e.g. I'm guessing this would be built something like this above the bedrooms is the loft space so there are 600mm centre attic trusses. I'm going to make the assumption that to get the light reflected I would need to board the trusses and then drop the ceiling, right? I'm also thinking that only a 50mm drop would be required? ceiling height is currently 2.4m so don't want to drop it too far really. so a 50mm MF bracket drop, then 9.5mm PB? I guess the other cheaper way to do this is to purchase LED coving profiles? something like this https://www.ultraleds.co.uk/u-shape-polymer-wall-coving.html and attach it 50mm/100mm down from the single skin of 12.5mm plasterboard? anyone have any suggestions/experience on how the best way to do this is? or have used the LED Coving profiles and what the effect is like compared to the dropped ceiling method? Link to comment Share on other sites More sharing options...
Pocster Posted June 19, 2023 Share Posted June 19, 2023 35 minutes ago, Thorfun said: afternoon all. I'm now thinking about a different dropped ceiling requirement. in the kids rooms we want to have the LED strips in a dropped ceiling look. e.g. I'm guessing this would be built something like this above the bedrooms is the loft space so there are 600mm centre attic trusses. I'm going to make the assumption that to get the light reflected I would need to board the trusses and then drop the ceiling, right? I'm also thinking that only a 50mm drop would be required? ceiling height is currently 2.4m so don't want to drop it too far really. so a 50mm MF bracket drop, then 9.5mm PB? I guess the other cheaper way to do this is to purchase LED coving profiles? something like this https://www.ultraleds.co.uk/u-shape-polymer-wall-coving.html and attach it 50mm/100mm down from the single skin of 12.5mm plasterboard? anyone have any suggestions/experience on how the best way to do this is? or have used the LED Coving profiles and what the effect is like compared to the dropped ceiling method? You know what I'm going to say...... 1 Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 12 minutes ago, pocster said: You know what I'm going to say...... probably something that also includes a double entendre Link to comment Share on other sites More sharing options...
Pocster Posted June 19, 2023 Share Posted June 19, 2023 8 minutes ago, Thorfun said: probably something that also includes a double entendre No . But you know … Link to comment Share on other sites More sharing options...
saveasteading Posted June 19, 2023 Share Posted June 19, 2023 Our joiner had an aversion to anything not straight, with character being of no interest. He wouldn't accept working on ties that weren't horizontal and in line. Eventually we agreed some areas could be levelled. He made vertical stubs, screwed to the sides of the ties, then struck a level and fixed counterbattens. Not metal framing but works the same so a TF system. Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 2 minutes ago, saveasteading said: Our joiner had an aversion to anything not straight, with character being of no interest. He wouldn't accept working on ties that weren't horizontal and in line. Eventually we agreed some areas could be levelled. He made vertical stubs, screwed to the sides of the ties, then struck a level and fixed counterbattens. Not metal framing but works the same so a TF system. actually, that's not a bad idea you know as I guess there's nothing stopping me (apart from potential load on the trusses) to just fixing 38mm or 50mm battens to the bottom of the trusses and plaster boarding to those, right? Link to comment Share on other sites More sharing options...
markc Posted June 19, 2023 Share Posted June 19, 2023 1 minute ago, Thorfun said: actually, that's not a bad idea you know as I guess there's nothing stopping me (apart from potential load on the trusses) to just fixing 38mm or 50mm battens to the bottom of the trusses and plaster boarding to those, right? Battens and PB will be fine, the additional load is well distributed and static. 1 Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 Just now, markc said: Battens and PB will be fine, the additional load is well distributed and static. also, i wouldn't need to board the entire ceiling above the dropped ceiling, right? just the bits around the edge Link to comment Share on other sites More sharing options...
markc Posted June 19, 2023 Share Posted June 19, 2023 12 minutes ago, Thorfun said: also, i wouldn't need to board the entire ceiling above the dropped ceiling, right? just the bits around the edge If it’s not already boarded then no, makes life really easy attaching the additional battens, do them at 90 degrees to the trusses to stabilise the bottom cords 3 Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 8 minutes ago, markc said: If it’s not already boarded then no, makes life really easy attaching the additional battens, do them at 90 degrees to the trusses to stabilise the bottom cords sounds like a plan to me! will run it passed the mrs to see what she says but i'm sold on this one. Link to comment Share on other sites More sharing options...
MortarThePoint Posted June 19, 2023 Share Posted June 19, 2023 6 hours ago, Thorfun said: above the bedrooms is the loft space so there are 600mm centre attic trusses. Is the loft living space? If it is, and the house is 3 storey, you will need this ceiling to be fire rated. That shouldn't rule out the battens, but you'll need to something neat with plasterboard (PB) to achieve a fire seal. Lots of strips of PB probably. Also check the fire properties of the LED strips as they may have a minimum distance to timber. PB in the way should solve that though. Something like the image below. If the plasterboard was 12.5mm then you could use 50mm x 38mm battens at 400mm c/c. If using thicker or thinner plasterboard, you could change batten thickness accordingly. Plasterboard strips can be screwed through with long PB screws, ensuring at least 25mm into timber. Also through the bottom most sheet and through the strips. Use a continuous bead of FireStop sealant between strips. You would probably want to use a plasterboard edge bead. No idea if this would meet regs, so you'll need to check that. Is there any indication as to how big the gap dimensions need to be. Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 7 minutes ago, MortarThePoint said: Is the loft living space? If it is, and the house is 3 storey, you will need this ceiling to be fire rated. That shouldn't rule out the battens, but you'll need to something neat with plasterboard (PB) to achieve a fire seal. Lots of strips of PB probably. Also check the fire properties of the LED strips as they may have a minimum distance to timber. PB in the way should solve that though. Something like the image below. If the plasterboard was 12.5mm then you could use 50mm x 38mm battens at 400mm c/c. If using thicker or thinner plasterboard, you could change batten thickness accordingly. Plasterboard strips can be screwed through with long PB screws, ensuring at least 25mm into timber. Also through the bottom most sheet and through the strips. Use a continuous bead of FireStop sealant between strips. You would probably want to use a plasterboard edge bead. No idea if this would meet regs, so you'll need to check that. Is there any indication as to how big the gap dimensions need to be. loft is not habitable so no issues with fire rating. I like your drawing and was thinking of using 38mm x 50mm battens but was going to use 12.5mm plasterboard at 600mm centres. my only concern was the bit of plasterboard 'overhanging' at the end of the run by the wall. seems a bit flimsy to just have it like that without any support. like someone could just put their hand up and yank it down. Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 19, 2023 Share Posted June 19, 2023 6 hours ago, markc said: attaching the additional battens, do them at 90 degrees to the trusses to stabilise the bottom cords This makes a world of difference for deflection, and I try to do this on every posi-joist'd project. Tres Bien. Link to comment Share on other sites More sharing options...
Thorfun Posted June 19, 2023 Author Share Posted June 19, 2023 1 minute ago, Nickfromwales said: This makes a world of difference for deflection, and I try to do this on every posi-joist'd project. Tres Bien. Actually these rooms are upstairs so the battens will be attached to attic trusses rather than posis. Sorry for any confusion!! I’ll still run the perpendicular to the trusses though. That just make sense. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 20, 2023 Share Posted June 20, 2023 9 hours ago, Thorfun said: Actually these rooms are upstairs so the battens will be attached to attic trusses rather than posis. Sorry for any confusion!! I’ll still run the perpendicular to the trusses though. That just make sense. They’ll still help a little, but the attic trusses are a slightly different beasts! 1 Link to comment Share on other sites More sharing options...
MortarThePoint Posted June 20, 2023 Share Posted June 20, 2023 There are some expensive profiles out there to do this. First link has an installation animation. ~£35/m seems steep to me, but may be the easiest way to go. https://www.darklightdesign.com/led-profilelement-dsl-profile/ https://www.ebay.co.uk/itm/273214350882 https://www.iluminize.com/en/shop/product/4604-led-drywall-profile-dsl-2m-long-for-floating-surfaces-with-a-substructure-363#attr= 1 Link to comment Share on other sites More sharing options...
Thorfun Posted June 20, 2023 Author Share Posted June 20, 2023 49 minutes ago, MortarThePoint said: There are some expensive profiles out there to do this. First link has an installation animation. ~£35/m seems steep to me, but may be the easiest way to go. https://www.darklightdesign.com/led-profilelement-dsl-profile/ https://www.ebay.co.uk/itm/273214350882 https://www.iluminize.com/en/shop/product/4604-led-drywall-profile-dsl-2m-long-for-floating-surfaces-with-a-substructure-363#attr= thanks for this. it is a nice solution albeit expensive but it does mean that the battens can be reduced to 25mm saving cost and ceiling height reduction and also plasterboard overhang which is something i was concerned about. i will investigate this solution! Link to comment Share on other sites More sharing options...
MortarThePoint Posted June 20, 2023 Share Posted June 20, 2023 12 hours ago, Thorfun said: thinking of using 38mm x 50mm battens but was going to use 12.5mm plasterboard at 600mm centres With 12.5mm PB, I'd use battens at 400mm centres. Minimal extra cost/weight/time. 1 Link to comment Share on other sites More sharing options...
Thorfun Posted June 20, 2023 Author Share Posted June 20, 2023 1 hour ago, MortarThePoint said: There are some expensive profiles out there to do this. First link has an installation animation. ~£35/m seems steep to me, but may be the easiest way to go. https://www.darklightdesign.com/led-profilelement-dsl-profile/ https://www.ebay.co.uk/itm/273214350882 https://www.iluminize.com/en/shop/product/4604-led-drywall-profile-dsl-2m-long-for-floating-surfaces-with-a-substructure-363#attr= so i've done a little bit of quick research and i can't justify the cost of these profiles when i could just glue these https://www.ultraleds.co.uk/standard-aluminium-channel-178-in-white-3-metre-length.html to the top of the plasterboard, right? even with the extra £0.44 per meter for the 38mm battens i make that a total of about an extra £18 per room on battens. doesn't even touch the cost of the specialist profiles. i'm not just being tight here, what would the justification be to use those specialist profiles? maybe in an area like they show in their video where you can actually see the edge of the dropped ceiling, e.g. above a kitchen island, but in my scenario where the dropped ceiling will be against a wall no one is ever going to see up there. Link to comment Share on other sites More sharing options...
Eric Posted June 20, 2023 Share Posted June 20, 2023 22 hours ago, Nickfromwales said: This makes a world of difference for deflection, and I try to do this on every posi-joist'd project. Tres Bien. Not to derail the thread but do you have any photos of this Nick? I have a kitchen & family room 10m x 7m with double JJI joists @ 400centres, I was actually wondering about fitting plywood before plasterboard? Link to comment Share on other sites More sharing options...
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