Browse Forums Building Standards; Getting It Right! 1 Jul 16, 2008 3:38 pm Hello All
I am in the process of renovation work & have a question or two regarding the use of the correct size/timber type of Bearer to put in place over a new window location. I'm removing two different sized windows from what has now become a single wet area room (was 3 roomed ie bathroom, toilet & vanity area). In place of those two I wish to install a single central window. The larger of the two existing but soon to be removed windows measures 1500 x 1500. Spanning over the top of this is a 185 x 35 bearer directly supporting the head plate & sitting in housing joints on the top of the studs. The smaller existing 900 x 600 window has an over bearer measuring 120 x 35. There is an ID marking on these bearers indicating 'Lodgepole Pine'...this is the same ID as on the existing window studs as opposed to the 'typical' 90 x 35 standard type Pine framework. I'll be leaving those bearers insitu but now need to add another Bearer to support over the new window location. The new window dimensions are 1200 x1000 the top of which will be aligned with the existing window height. OK, here's the question...probably sounds silly but I prefer to know & use the correct stuff. Q. What wood type/size should I use for the new 1200W x 1000H opening? Thanks in advance. Cheers Cliffy Timber Lintel to Use 2Aug 09, 2008 9:15 pm Hi Cliffy, the question needs to be answered very carefully as what you are doing constitutes a structural renovation. And technically requires a permit. To answer your question though you need to consult standards australia"AS 1684.4-2006 Residential timber-framed construction Australian Standard (Part 4 Simplified non-cyclonic areas)"
You need to give me me more information, i need to know the rafter or truss span (distance from one side of your house to the other, from window to opposite side, if you have trussed roof). Assuming it is between 6 and 9 metres and you use seasoned timber, the span over the window is 1200 wide you can use either 90x45 F17 for a sheet roof but if you have tiles you will need to use120x45 MGP10 or 2 90x45 F17 side by side. If you use unseasoned timber such as F11 or F8 you will need larger timbers. There are many options. If you want a copy of the table i can fax you one just pm me Hope this helps mate! Michael. Afterthought... the window is 1200 wide so the span over will be slightly larger. you will be better off calculating it from the 1500 table which is worst case 120x45 F27 Re: Over Window Bearer 3Aug 15, 2008 2:04 pm I fuly agree with Michael, But i'd like to add a bit more.
This is major danger home renovation at its best. From the thread above ive assumed we're actually talking lintols here, not bearers. If im correct in this assumption, lintols hold big stuff up like...roofs! I would be running off to a structural engineer and getting this 'lintol' sized before you do anything. The structural member required will have to factor in, existing roof structure, existing roof finish (tiles are heavier than sheeting) etc etc. Dont be a hero, use the professionals. Pat the draftie. Re: Over Window Bearer 4Aug 15, 2008 7:23 pm You can prop up the trusses/ ceiling joists with some framing timber to take the weight whilst you fit the lintel.
With only a small span such as 1200mm, you won't need anything hefty as mentioned. Larger spans generally use F27 KD hardwoodor LVL/LGL's If you want to play it safe and use a similar size to the existing lintel, use a 190x35 F27 hardwood or 190x36 LVL13 ( treated if your worried about termites) Seconded; we just used these last weekend to build a small deck. They worked perfectly as we have bluestone in the area where we wanted to build so digging down was not… 8 9065 Hi Mrboh Just wondering if you have any BAL or flame zone issues on your block, as getting compliance with BAL requirements whilst doing bearers and joists is tough. Not… 1 8360 yep you need a joint, foam is easiest, will look fine once rendered with a joint. 2 5234 |