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TO MAKE A GUTTER MITRE

Measure fascia from the corner 
of the fascia to existing gutter 
allowing 100mm for gutter lap.

1

Place length of gutter upside 
down on the ground so that the 
base of the gutter is facing you.

2

Mark where the fascia corner will 
occur (point 

A

) on the back of 

gutter, and using a 90˚ square 

and pencil, draw a line across the  
outside of the back of gutter.

3

On the back of the gutter place a further 2 marks, each equal to the width of 

the gutter (at points 

B

 and 

C

) to extend beyond the fascia corner. The central 

mark 

B

 should be extended completely around the outside of the gutter using 

the 90

˚ square and pencil.

4

On the base of gutter, draw a line to connect the continuous line from 

B1

 to 

both 

A

 and 

C

. Mark a line 10mm away from, but parallel to 

A-B1

, and extend 

this across the back of the gutter. This will produce a “lap” when the gutter 

mitre is formed. This parallel line should  
also extend up the back  
of the gutter to 

A1

.

5

Using tinsnips, cut along the 
line on one side and on the 
other side, cut on the parallel 

line which is 10mm in from the  
original line drawn connecting  

A-B1

. You will cut out the  

complete V marked into the gutter. 
In addition, remove excess  
material at 

A

 and 

B1

 to allow the 

outside of the gutter to fold easily, 
and the tags to overlap.

6

 For a square gutter cut a 45˚

 

notch into the bead of the 
gutter using a hacksaw and 

tin snips at 

B1

 directly  in line with 

the point of the V on the base of the 
gutter. For gutters with an external 

bead, such as quad (D) or OG, a 

single hacksaw cut is used to cut the 
bead. A mitre gusset must then be 
attached to complete the bead line. 

7

Fold the gutter around until the back 
sections touch each other. Fold tag 
inside the back gutter. Rivet and  

silicone. You have produced an external  
gutter mitre. To produce an internal 
gutter mitre, reverse your V line marks on 
the gutter so that point 

B1

 is exchanged 

for point 

B

 and the face of the gutter is 

cut out not the back. Then follow the 
above steps. With some gutters a mitre 

gusset will be required to cover any gap in 

the gutter bead. 

8

B1

B1

A

A

A1

A

B

B

A1

A1

A

 C

10mm

 C

COMPLY WITH REGULATIONS

All building work must be carried out in accordance with the Building Code of Australia (BCA). 
This code refers to various Australian Standards, which provides acceptable standards of 
product manufacture and building practice. These include:

• AS/NZ 3500.3  Plumbing and Drainage, Stormwater Drainage
• AS/NZS 3500.5  National Plumbing and Drainage, Domestic Installations

Prospective users of Stratco materials should first ensure that they understand these 

requirements  and  any  other  state  or  territory  specific  regulations  that  may  apply.  In  some 
states of Australia (eg. NSW and Victoria) work involving the installation of roofing, rainwater 
goods and drainage may need to be installed by a suitably qualified tradesperson, and comply 
with statutory warranties. (Refer www.deus.nsw.gov.au/water/plumbing.asp)

Care should also be taken in the design and installation of roof drainage systems given the 
wide range of factors such as rainfall intensity, gutter capacity and selection, number and 
placement of downpipes and sumps. Care should also be taken to select the most suitable 

gutter style. Gutters that have a front higher than the back are popular to hide the exposed 

ends of roofing, but unless manufactured with optional slots or fixed with the bead lower 
than the top of the fascia may contravene building regulations. Other fixing options can be 
used to eliminate overflow from the back of a gutter into a building. These include additional 
overflow weirs placed either in the gutter or stop end, rainheads with overflow weirs, custom 
back flashings, leaving a gap between the fascia and gutter back, or other proprietary systems 
or trade solutions.

Up to date information about Stratco products, spans, installation requirements and technical 

advice can be found on our website at www.stratco.com.au and it is advisable to obtain current 

information prior to ordering any materials. If additional information is required contact the 

Stratco office in your state.

REMEMBER TO

• Waterproof each rivet with silicone sealant applied on the “weather” side.
• The minimum fall of guttering to the downpipe end is 1 in 500 (or 12mm every 6m).

CONTACT

1300 165 165

www.stratco.com.au

All brands and logos/images accompanied by ® or ™ are trade 
marks of Stratco (Australia) Pty Limited.

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