-oXo- Posted March 10, 2012 Report Share Posted March 10, 2012 (edited) Hello Wonder if anyone can help to save me calling round on the phone. Ok so I am going to put a roof on an old garage at the end of my yard to build a workshop/gunstore/mancave. The roof spans 5.5x5 meters. Will 9x2's stretch 5 metres without bowing? It will be a flat roof going on there after. Just not sure on the size of joist to use. Or maybe them nice I beams? :hmm: All abuse and ideas appreciated. Edited March 10, 2012 by -oXo- Quote Link to comment Share on other sites More sharing options...
WelshLamb Posted March 10, 2012 Report Share Posted March 10, 2012 9x2 should be fine. I think our joists are 8x2 Quote Link to comment Share on other sites More sharing options...
Fisherman Mike Posted March 10, 2012 Report Share Posted March 10, 2012 (edited) Which way are you spanning ? if the 5m way 225 x 50 grade C16 @ 400 centres will just creep in at the 5.09m mark if the 5.5 way 225 x 75 grade C16 @ 400 centres. Dont forget to block them midspan or twice at third span to stop them twisting. Edited March 10, 2012 by Fisherman Mike Quote Link to comment Share on other sites More sharing options...
-oXo- Posted March 10, 2012 Author Report Share Posted March 10, 2012 Which way are you spanning ? if the 5m way 225 x 50 grade C16 @ 400 centres will just creep in at the 5.09m mark if the 5.5 way 225 x 75 grade C16 @ 400 centres. Dont forget to block them midspan or twice at third span to stop them twisting. It shall be the 5m way and thanks for that perfect answer. Quote Link to comment Share on other sites More sharing options...
nabbers Posted March 10, 2012 Report Share Posted March 10, 2012 Google "Span tables" they will tell you what build regulations stipulate. All the Council Building Standards departments used to link to them off their websites, but in this blame/claim culture, most have pulled them.http://www.dfpni.gov.uk/d.pdf Here are some good ones...http://www.dfpni.gov.uk/d.pdf Don't go for minimum, it's a false economy and when you put them on sight down them and fit convex bow upwards! And be careful where you drill them for cables! Quote Link to comment Share on other sites More sharing options...
Fisherman Mike Posted March 10, 2012 Report Share Posted March 10, 2012 (edited) It shall be the 5m way and thanks for that perfect answer. Your welcome 36 years in the business I hope Ive learned something Try Read Brothers in Norwich Google "Span tables" they will tell you what build regulations stipulate. All the Council Building Standards departments used to link to them off their websites, but in this blame/claim culture, most have pulled them.http://www.dfpni.gov.uk/d.pdf Here are some good ones...http://www.dfpni.gov.uk/d.pdf Don't go for minimum, it's a false economy and when you put them on sight down them and fit convex bow upwards! And be careful where you drill them for cables! Sound advice... follow the middle third rule and you should be ok. Use the smallest bit capable of pulling through the cable. Edited March 10, 2012 by Fisherman Mike Quote Link to comment Share on other sites More sharing options...
monkey001 Posted March 11, 2012 Report Share Posted March 11, 2012 Don't forget restraining straps for the wall plates if they aren't already there. Quote Link to comment Share on other sites More sharing options...
DSPUK Posted March 11, 2012 Report Share Posted March 11, 2012 A mate used those manufactured I beams with metal framing in them - was really impressed - no twisting and plenty of room to run cables and pipes without drilling. Dave Quote Link to comment Share on other sites More sharing options...
mfletch Posted March 11, 2012 Report Share Posted March 11, 2012 (edited) As above I would see if you can get hold of these, Edited March 11, 2012 by mfletch Quote Link to comment Share on other sites More sharing options...
-oXo- Posted March 11, 2012 Author Report Share Posted March 11, 2012 (edited) Yeah I have seen those. Any idea on the price difference over plain 9x2's, considering it is just a bit of osb board must be lower in price? Also on suppliers? Edited March 11, 2012 by -oXo- Quote Link to comment Share on other sites More sharing options...
-oXo- Posted March 11, 2012 Author Report Share Posted March 11, 2012 Yeah I have seen those. Any idea on the price difference over plain 9x2's, considering it is just a bit of osb board must be lower in price? Also on suppliers? Rough guess on 9x2s for 5m is about £20 and I need 14 of them Quote Link to comment Share on other sites More sharing options...
DSPUK Posted March 11, 2012 Report Share Posted March 11, 2012 I was thinking more of the metal web sort as in here http://www.timberframe.co.uk/index.php/engineered-wood/ Dave Quote Link to comment Share on other sites More sharing options...
nabbers Posted March 11, 2012 Report Share Posted March 11, 2012 (edited) A router to groove out the 4x2s and some good wood glue, I reckon you could knock up your own I joists for pennies! Personally I'd get some steel in there so you can winch out Chevy engines etc. Check out my build.. 2x 9m span 550 x 200 each in 3 sections... http://i220.photobucket.com/albums/dd6/timber-works/11432_1250954626768_1016576871_30823466_1262435_a.jpg Edited March 11, 2012 by nabbers Quote Link to comment Share on other sites More sharing options...
Beretta28g Posted March 11, 2012 Report Share Posted March 11, 2012 We have used 12x3 before as they were going spare and cheap. Very strong roof too! Quote Link to comment Share on other sites More sharing options...
rusty50 Posted March 11, 2012 Report Share Posted March 11, 2012 I Beams are best by far places like jewsons will correctly spec your requirements Ive used them at 5.8mtr and very little flexing and interlocking boards are solidly fixed using foaming glue in joints a nail gun down Quote Link to comment Share on other sites More sharing options...
jef Posted March 12, 2012 Report Share Posted March 12, 2012 I beams or fin joists are far more expensive to buy. Fit a couple of rows of herringbone dwangs (scottish noggings), makes for a far sturdier job. JF Quote Link to comment Share on other sites More sharing options...
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