Browse Forums Building A New House 1 Aug 12, 2008 5:57 pm I would like advice on whether to use box gutters. I have had a very modern house designed that basically fully uses box gutters, but I seem to be getting warnings that it's not the way to go. One builder even basically said that he would not want to build it as is. Another builder said they are fine. Who do I trust? BTW I'm in Sydney.
I'd upload the plans if I knew how... Thanks for your help. Re: Box gutters - advice please - would you use? 2Aug 12, 2008 6:30 pm I'm guessing you are talking about internal box gutters?
There are a few issues with these. The main one is that if you have an overflow of the gutter due to a blocked downpipe then the water will inevitably make it's way inside the roof space and you have water damage. This will happen regardless of whether it is a valley gutter (in the middle of the building with a roof each side draining to it) or a gutter just inside a parapet/outer wall. With a normal eaves gutter the overflow happens externally. One way around this is having overflow pops either along the parapet wall through the side of the gutter or through the bottom of the gutter and either out the parapet or under the eaves. The preferred method is through the bottom of the gutter as they work more efficiently. The other option is to use overflows at the ends, which is the only option for a valley gutter (most of the time this is where your downpipe will be so you just use a rain head at the end of the gutter). Overflows are generally very inefficient so you need at least twice as many as you have downpipes. Then obviously you have the problem of where does the water go when it hits the ground - for this you want to landscape your block to a pit to prevent water travelling back towards the house. Another problem with internal box gutters is the you really want at least two downpipes per gutter as one on it's own is far too easy to block. Also if you have expansion joints for a very long gutter it's preferable to have a flat expansion joint made of rubber. Last of all once you do that roof maintenance will be a priority. Roof drainage design can be quite involving and it something you definitely don't want to get wrong. I would suggest you find a consultant (civil engineer) that can make sure the design is satisfactory and complies to at least a 1 in 100 year storm, which for Sydney is about 240mm per hour of rain. Do not be convinced to go without overflows. Just about all shopping centres and modern buildings that are designed to be aesthetically pleasing have internal box gutters so it's not an impossible task. You just have to make sure it's done right. Re: Box gutters - advice please - would you use? 3Aug 12, 2008 7:05 pm One last piece of advice I can give is that the lifespan of even galvanized gutters is usually no more than 20 years. This is especially the case for box gutters as many builders tend not to design enough fall into them (I seem to remember 1:50 is the minimum). So unless you feel like getting up on the roof to paint the gutters every 5 years (they are expensive to replace) I recommend using stainless steel for the gutters. This will mean that you can design for less fall if you need to and they will never need replacing or painting. Re: Box gutters - advice please - would you use? 4Aug 12, 2008 9:25 pm In my experience roofing contractors are even reluctant to install box gutters, however some home designs demand them.
my last home and current home have box gutters and if installed with enough fall and adequate overflows you shouldnt have any problems, i havn't, and in Brisbane we are subjected to heavy summer downfalls, the comments from mozz are correct, however if you like your design talk to some roofing contractors to get their advice. the builder who said he would be reluctant to build your home with box gutters has probably had problems before and is covering himself from any more headaches. Re: Box gutters - advice please - would you use? 5Aug 12, 2008 9:26 pm In my experience roofing contractors are even reluctant to install box gutters, however some home designs demand them.
my last home and current home have box gutters and if installed with enough fall and adequate overflows you shouldnt have any problems, i havn't, and in Brisbane we are subjected to heavy summer downfalls, the comments from mozz are correct, however if you like your design talk to some roofing contractors to get their advice. the builder who said he would be reluctant to build your home with box gutters has probably had problems before and is covering himself from any more headaches. Re: Box gutters - advice please - would you use? 6Aug 12, 2008 11:41 pm Here's my 2 cents worth.
Ive seen box gutters done on older buildings (20+ years old) and they still work fine, because they were installed properly with falls, overflow pops, properly jointed and flashed by pros (professionals that is!). Then Ive seen box gutters on new buildings(2+ yeas old) and they leak like a sive in rain, because of incorrect falls, no overflow allowance, poorly jointed and flashed, and because they were installed by cowboys. Conclusion: If you are going to do, do it once, and do it right. Last cent worth, Im presuming your using box gutters to get that square architectural edge to your building facade, and eliminating the eaves overhang. Consider access to and on top of these gutters, most box gutters Ive done are approx 300mm wide (depending on roof area) and usually they need to be really strongly supported because idiots walk in them when up on the roof. This idiot weight if not supported will buckle the gutter, break flashings, break seals, and mess up all the falls of the gutter. Pat the draftie Plasterboard Gyprock is very popular as a reveal liner these days. You need to provide a way of supporting it, we use a modified timber reveal or bracket. You will be… 1 2978 Bought in Nov 21 at the height of the market (classic). Good area, atrocious floor plan. BUT has land out to the left-hand side that we can extend out on (see second… 0 8727 Thanks mate. Yeah good points! Leaning towards Option 3 to get a bit extra space in the cabinets but not going too crazy high (and expensive). Would require a mini… 13 39259 |