Minimum Stair Tread Size

The greatest depth at the 12 inch mark must not exceed the smallest on any other tread by more than 0 375 inches.

Minimum stair tread size.

Stair tread depths shall be 11 inches 279 mm minimum. There isn t one unifying rule for every kind of material stair treads may be built out of. According to building codes stair tread for wood stairs has to be anywhere from 1 to 1 in thickness. The minimum general tread depth remains 11 inches but it is measured at a right angle from the leading tread edge that is 12 inches from the narrowest side.

The stair tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at right angle to the tread s leading edge. Handrail height to be placed a minimum 34 inches to 38 inches. Stair tread depths shall be 11 inches 279 mm minimum. Harvard university lists typical tread sizes between 8 and 11 1 2 inches.

When it comes to other materials the thickness may differ. This is because stair treads can be crafted from thick oak to think stainless steel. This distance must be at least 10 inches. However the americans with disabilities act ada lists the minimum tread size as 11 inches which would be the effective minimum and likely the average size of the tread for any stairs built for public use.

The minimum tread size is commonly stated as 9 inches for residential construction. The riser height shall be measured vertically between the leading edges of adjacent treads. However if the steps do not have nosings and the steps have solid risers not open risers the minimum tread depth is 11 inches. This narrow side must have a minimum tread depth of 10 inches.

As general rules of thumb for achieving comfortable relationships between riser and tread dimensions the following formulas can be used. Handrail graspability to be either type i or ii with a minimum 1 1 2 inch clearance from a wall. Staircase risers should be adequately deep to allow a majority of your foot to have enough room to rest on the stair. Minimum 10 inch stair tread depth with nosing or minimum 11 inches with no nosing.