Bottom Tread?

[KZQuixote]

2009 IRC Section R308.4 Hazardous locations.(8)

Glazing adjacent to stairways within 60 inches horizontally of the bottom tread...

Does the bottom tread sit atop the first riser? Or is the portion of the floor or landing in front of the first riser considered the bottom tread?

TIA

Bill

 

[mtlogcabin]

You can't have a tread if you don't have a riser.

You don't usually trip or fall off of a landing but you do trip and fall off of a tread.

Or is the portion of the floor or landing in front of the first riser considered the bottom tread? No

 

[fatboy]

I agree with mt......the nosing of the first tread.

 

[Francis Vineyard]

The way it reads if the riser is 8 inches then the measurement including the thickness of the tread would be approximate 68 inches above the floor or landing.

8. Glazing adjacent to stairways within 60 inches (1524 mm) horizontally of the bottom tread of a stairway in any direction when the exposed surface of the glazing is less than 60 inches (1524 mm) above the nose of the tread.

It is not uncommon to measure 60 inches up from the floor or landing beyond bottom riser.

Francis

 

[steveray]

I'd go (and do) with tread...not landing.....found it on inspection a few times at roughs....

 

[Francis Vineyard]

Remembered 2012 change removed nosing and if the window sill is 36 inches or more above the floor or landing safety glazing is not required; R308.4.6 & R308.4.7. so it follows the guard height for fall protection.

Can see the Significant Changes here Maryland Amendments

Francis