Box Gutter Building Regulations

Oversize gutters will look wrong.

Box gutter building regulations.

They also give calculations for working out the flow rate that guttering must meet. They should not be confused with so called valley gutters or valley flashings which occur at the non parallel intersection of roof surfaces typically at right angled internal corners of pitched roofs. Box gutters get a lot of moist leaves and debris and these can shorten its life so the rule of thumb is to have the box gutter material as good or better in the corrosion department than the roofing material. The regulations require that guttering has allowances for water to overflow gutters in a way that does not cause water to flow back into the structure.

The assembly is made up of four components consisting of two internal end caps one slip cover plate and one slip joint slice plate. This effectively states that all box gutters must allow for 30mm of freeboard which is from the overflow point eg. This will prevent water damage in the event of gutters overflowing either due to high rainfall or a blockage. See local building codes to allow for proper thermal expansion of our commercial box gutter system.

Sometimes i see architectural specifications nominating a colorbond roof with a zincalume box gutter. Have a minimum depth of 75mm at the high end. Box gutters are essentially placed between parallel surfaces as in a valley between parallel roofs or at the junction of a roof and a parapet wall. The building regulations set out requirements for many aspects of guttering.

As an alternative the top of the rainhead may be installed so that it is no higher than 50 per cent of the flow depth of the box gutter consistent with saa hb39 installation code for metal roof and wall cladding section 5 clause 5 7 3 and figure 5 7 3to prevent internal flooding or damage to the building or contents see figure 2. Here are some new building regs drawings including mansard roof edge parapet wall box gutter verge detail pitched roof flat roof abutment threshold welted drip for external gutter pitched roof to wall junction pipe through wall joist hangers window frame window lintel window sill manholes soakaway etc. Rainhead overflow or specific box gutter overflow must be at least 30mm below the height of the back of the box gutter. Also some timber frame details.

The regulations make sure that rainwater drains away from buildings. These include the positioning and size of downpipes and the acceptable drainage options. All domestic box gutters must be a minimum of 200mm wide and 75mm deep. Deepflow can be utilised where fall is an issue.

Read more about compliant guttering options what does it mean for installers. Have a minimum width of 300mm for commercial installations 200mm for domestic installations. Usual rule of thumb is 25m2 into a 115mm gutter with 1 downpipe of 68mm.