# Forum Home Renovation Stairs, Steps and Ramps  BCA for Balustrade on staircase

## Schumi

Hi All, 
I am a little confused in regards to the minimum height required for fixed balustrading on a staircase. 
I have an external deck with a 7 step staircase which is greater than 1m above the groung which I will be fitting balustrading to, 50mm gap at base of decking bottom rail, and 950mm balustrading to give me the required 1m height.  
When i have priced the product through several companies they have also quoted on the same height as a requirement for the staircase, From research that i have done I seem to come up with a minimum requirement of 865mm for stairs, Is this correct? 
1m on a staircase seems a little high.   
Thanks 
Anthony

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## Hoppy

The BCA requires in Clause 3.9.2.3 The height to be not less than 865mm above the nosing of the tread. You also need to ensure that no sphere larger than 125mm can pass through the balustrading at any point.
be carefull of the bottom rail going down the stairs, if they position that rail 50mm above the nosing and run the rail parallel with the slope of the stair you may end up with a large opening at the junction of tread and the riser.

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## ringtail

Its a bit of a joke really. The 865mm is measured vertically from the nose of the tread. So the easy way to understand it is - 
Imagine a string line that runs from the nose of the top tread or edge of the deck to the nose of the bottom tread. If the stairs are built properly the string line will be just touching the nose of each tread. From this string line, measure vertically up 125 mm at the top and bottom on your newel posts. Run another line between these marks and thats where the bottom rail or cable goes ( if you want that clearance - I run less to be safe). This is where it gets nuts. If you measure the gap at the back of the treads up to the bottom string line, the opening is massive - like 250 mm + and yet perfectly legal as the gap is measured from the nosing line. Go figure. You still have to make sure you dont have more than 125 mm between your treads though. This is only a problem with open staircases obviously. If you have timber stringers you wont have the sides of the treads open.

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## Schumi

Thanks for the reply guys, I will run it at 900 to play it safe,  
Anthony

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