Browse Forums Renovation + Home Improvement 1 Jun 18, 2014 9:50 pm Hi all, We are planning on doing an extension and looking at our options. Having trouble working out how the roof can be done over the extension The current house is an "L" shape with a tiled gable roof: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ The new layout changes this to a "U" shape, normally this would be okay except we are also extending the inside of the "U", so we can't use the existing roof as is. Here is the new layout with the old roof line shown as dotted lines, and the old external wall as the faded blue line. The bottom right part of the extension is a garage if that makes any difference. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ The main things we are wondering: 1) Is there any way to cover the new part while still keeping a tiled roof? Or is this too complicated due to the pitch of the tiles? 2) If we have to change to colourbond, how would you do it so that we don't need to change too much of the existing roof frame? (It's an old construction, doesn't have trusses). 3) Is it possible for it to be cheaper to remove the existing tiled roof, roof frame, and start from scratch? Re: Help with roof design 2Jun 20, 2014 11:45 am 1) If you are keeping the same pitch you can leave all the existing roof in place, build the extension and remove the section of roof tiles necessary so you can cut the new roof into the old. A carpenter would do this easily and all you'd need is to hire a couple of big tarps for a week while you do this. Probably half of your roof would remain and you'd have to adjust part of the old to suit with the extension obviously needing new roof framing. 2) Easy, just build it as for a tiled roof and when you are ready just strip off the tiles and battens the install sarking or blanket, new battens and CB roof sheeting. You have to remember that a tiled roof is a lot heavier than CB 25kg/sq m vs 10kg/sq m 3) possibly but I doubt it. but you may end up having to replace most of your ceilings in those existing rooms too if you did replace all the roof framing. I'd leave most of the existing roofing in place remove some of the ridges and just nail the new rafters alongside the old - less hassle, less rubbish to remove etc. You will probably lose the gable at the front too. Stewie Re: Help with roof design 3Jun 20, 2014 12:43 pm Thanks for the suggestions. So are you saying we could keep the same pitch and just make it extend over the new part, basically increasing the overall height of the roof? I don't have a problem keeping the same pitch, it would just make the roof quite tall - but I guess there is nothing wrong with that. Re: Help with roof design 4Jun 20, 2014 1:13 pm Is this kind of what you meant by keeping the same pitch? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Will still need to sort out how the bottom right part of the roof joins in, and wether to keep the gable or change to hip. I guess it's increasing the main roof by 2.5m width (1.25 on either side of peak), which is only an extra 0.5m in height at ~22 degree pitch. Re: Help with roof design 5Jun 21, 2014 12:30 pm Quote: Is this kind of what you meant by keeping the same pitch? Yes pitch = slope. So all you would do is increase the length of the rafters over the greater width of the house while maintaining the same pitch of 22º. Quote: Will still need to sort out how the bottom right part of the roof joins in, and wether to keep the gable or change to hip. Personally, I'd get rid of the gables ( depending on the style of your existing house and what you want it to eventually look like ). They are a maintenance issue and can look a bit dated sometimes ( once again depending on your style house etc ). It is sometimes easier to cut a new section of roof into a hip rather than into gables too. Stewie Re: Help with roof design 6Jun 21, 2014 1:23 pm I imported your floor plan into my CAD program and drew a roof - 22º roof pitch with 450mm eaves . Interestingly it spat it out and said " roof too complex to compute" so I broke it down into two. Here it is roughly ( forget about the rear gables for a mo. ) Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ As you can see in this scenario of hipped roof all round and the one below with gables on the two roofs at the front you will have a problem where the new meets the old ( you'd need a box gutter ). Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ The front existing gable would also need to be clipped to accomodate the newer one. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ With no gables and a hipped roof all round... Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ As you can see a reasonably complex roof now and despite what I said before you may not keep much of the old roof at all. Stewie Re: Help with roof design 7Jun 21, 2014 2:31 pm Thanks for doing that, I do prefer the hip to gable, and really want to avoid a box gutter.
Is that last design still 22 degree? Would it make things easier overall if we end up changing to colorbond and can go lower? The other option we have is to square off the bottom left corner so it all lines up on the left side, but I'm not sure if that would help, and might even make things worse if we go with hip. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Also, ignoring the hips for a moment, would something like this work? (I guess not since the height of the gutter at that short valley would be too high?) Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Help with roof design 8Jun 21, 2014 3:15 pm Actually is there anything wrong with this? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Should work with your early hip design as well? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ I found this link which has something similar http://www.builderbill-diy-help.com/hou ... nsion.html Re: Help with roof design 9Jun 21, 2014 6:58 pm Quote: Is that last design still 22 degree? Would it make things easier overall if we end up changing to colorbond and can go lower? Yes all 22º. It would end up being much the same no matter what the roof covering. You can go down to 7º with CB but I think thats too low. I wouldn't have anything less than 15º and even that might not suit the style of your house. Quote: Also, ignoring the hips for a moment, would something like this work? (I guess not since the height of the gutter at that short valley would be too high?) Yes, but I think no matter what you choose you should consider what it looks like from the front - all the other sides don't matter anywhere near as much. Stewie Re: Help with roof design 10Jun 22, 2014 8:30 pm Stewie D Yes, but I think no matter what you choose you should consider what it looks like from the front - all the other sides don't matter anywhere near as much. Yeah I think hip looks better overall, though some gables are nice as well. Not sure if you saw the hip designs in my last post, but it looks like that should work. Re: Help with roof design 12Jun 22, 2014 10:05 pm Sorry that was poorly worded, what I mean is we are making that inside part of the U fatter, which is where we have extended past the previous wall by 2.5m or so (see the blue lines for the existing wall). So we aren't filling the whole "U" in, but we are extending a little inside it which is why we can't keep that part of the roof as is. Re: Help with roof design 15Jun 30, 2014 6:31 am I work with roof designs all day, every day. I am very impressed stewie, well done... steve@everlastpatios.com.au www.everlastpatios.com.au G'day I'm trying to put in some privacy screening on my rental rooftop on a tight budget. I've already invested about $500 in the supplies for this. The issue is… 0 32245 Once you know the basics, the rest is easy. Read my post in the thread linked below. viewtopic.php?p=1919271#p1919271 2 19528 Although I am a big opponent of using waffle pod slabs over H2/P soils under any circumstances, in your case I would certainly opt in to keep piers under central… 1 2434 |