Browse Forums General Discussion 1 Apr 06, 2014 4:46 pm Well, I finally got a roofer to come and quote for a flat roof replacement at the back of my house. It seems every roofer in Sydney has a huge backlog of work because of the persistent rain. The roofer will install the usual foil-backed blanket under the metal roof, and I will supply some batts to put between the rafters. The roofer is the father of a friend of my daughter's; he didn't really see the need for the extra batts, so I said I would supply them just to make things easier.
I now have to work out sight unseen the space available for the batts - working off both the height and spacing of the rafters. Heightwise, I have poked a chopstick through the hole in my ceiling and believe the rafters are 150mm deep. At that point I felt a spongy layer, which I believe is the old insulation blanket. I was able to push the chopstick a further 50mm approx., which would be the additional height of the battens. I assume I can choose batts up to 150mm in depth, so the new battens can be nailed on without the batts getting in the way. Now to work out how close the rafters are together. The width of the room is 4200mm, and I guess the rafters could be at 450mm or 600mm centres. I have been tapping on the underside of the ceiling for any difference in the sound that's made, but it hasn't really helped me. Looking at the roof from above, the battens appear to be 600mm apart, since that is where the screws are. The roofing material is aluminium kliplok type stuff. The roof is on a 1960s extension. Is there anyone can suggest how I can accurately guess at the rafter spacing? If I buy the batts too wide then it will hold up progress while I race to Bunnings to swap them over, assuming they have something else in stock. The roofer didn't want to pull up any sheets to look at the spacing because he didn't want to make my leak any worse, given rain was predicted. Re: How can I figure out rafting spacing in my flat roof? 2Apr 06, 2014 8:39 pm Hi nibbles55, You have done some great detective work on your roof framing. I think the 600 spacing is probably the most likely given that's where the screws are. I think your assumptions on the thickness sound reasonable as well. 600 centres would also work with the 4200 room width as it is 7 bays. Also have you tried using a stud finder? You may be able to hire one. They are useful for walls, I have never used one on a ceiling but I wouldn't imagine it would be different. Good luck with it all. Cheers, Jenny Need hints, tips and inspiration? Join me on my Facebook page: https://www.facebook.com/ournewhomecoach Who am I? See my LinkedIn page: http://www.linkedin.com/pub/jennifer-crawford/1a/429/296 Re: How can I figure out rafter spacing in my flat roof? 3Apr 07, 2014 9:54 am Thanks for the input, Jenny. I did come across something on the web last night related to someone wanting to find the location of his ceiling joists in order to have some lighting put in. He was advised to make some small holes and use a piece of wire bent at 90 degrees to rotate in the hole, and see if the wire hits the joists as you spin it around. Depending how long you make the wire, you can get a feel for how far the hole is from the joists either side of the hole. Well, I'm going to give that a try. If that fails, a stud finder should be able to pick up the nails that have been used to attach the plasterboard to the rafters/joists, and they are actually quite cheap at Bunnings. Re: How can I figure out rafter spacing in my flat roof? 4Apr 08, 2014 12:58 am Unscrew a roof sheet and have a look. You dont know if ceiling battens have been used which are normally at 450c so you could get a false reading. good luck consider putting in wall WC instead of robe in the same bedroom, then it might be doable to hook up to the existing piping. 4 6602 Hi all I need a guidance on how far I need to space expansion joints in the concrete driveway and its type (keyway/foam.) Contraction joints are at 3m max for a 125 slab. Thanks 0 10900 I would suggest you simply go and talk to council about your proposal, most councils are getting onboard with ancillary dwellings. There is no benefit in keeping it… 1 4069 |