Roof Cricket (Saddle) Framing Calculator

SettingsSettings for this calculationUS

Market

Imperial · sales tax

Obstruction Width (Facing Up-Slope)

The width of the chimney or obstruction as measured facing up the roof slope.

This is the dimension the cricket's ridge must span across to divert water around both sides of the obstruction.

Main Roof Pitch (rise per 12)

The pitch of the main roof the cricket ties into.

A symmetric cricket typically matches the main roof's pitch on each of its two sloped faces.

Cricket ridge height

1 ft

High confidence

Then change the inputs to see how far the answer moves.

Show calculation logic

How this was calculated

Formula source(s)

A symmetric roof cricket's ridge height = half the obstruction's up-slope-facing width x the main roof's pitch ratio

Inputs used

Obstruction Width (Facing Up-Slope): 4 ft
Main Roof Pitch (rise per 12): 6

Final result1 ft

What this calculation does not cover

Does not tell you whether a cricket is required. Codes generally call for a cricket or saddle behind any chimney more than about 760 mm (30 in) wide measured across the slope, and the trigger is that width — not the chimney's height above the roof, and not the roofing material. Below it, back flashing alone is normally the detail.
Water leaves down the valleys, and a valley always falls at a shallower angle than the two planes that form it. On a low-slope main roof, a cricket built at the main pitch produces valleys whose fall can drop below the minimum slope the covering is listed for, which is how a correctly framed cricket ends up holding a puddle and a line of debris along each side.

Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1

Regulatory standards & verification citations1

A symmetric roof cricket's ridge height = half the obstruction's up-slope-facing width x the main roof's pitch ratio

Cite this page

Your workspace

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Tools and safety for this job

To frame a stud wall and cut framing lumber. Generic types, no brands, no prices.

Protection this work requires

Hardwood dust is a recognised carcinogen: extract at the tool and wear a P2/N95 respirator when cutting or sanding indoors.
Saws, grinders and breakers run above 85 dB, where hearing damage accumulates and does not recover: defenders or plugs for every cut, not just the long ones.
Nailing, chiselling and cutting all throw fragments: glasses to EN 166 or ANSI Z87.1, and goggles rather than glasses overhead.

Show the 9 tools this job needs

Essential

Circular saw
Claw hammer
Combination or framing square
Spirit level
Tape measure

Recommended

Chalk line
Framing nailer
Mitre saw

Optional

Hand saw

Also needed as materials: chalk refill, circular saw blades, framing nails, fuel cells, mitre saw blades.

what each carpentry tool is for, and the spec that decides which to buy where one does.

Now that you have the number

These guides cover the work this quantity is for — the first ones run this calculator inside the section that raises the question.

Framing a Skylight Openinguses this calculator

One catalogue code decides the opening, the header, the curb and the saddle above it — worked in that order, from the unit outward.

Detailing a Parapet and the Cricket Behind a Curb

Leadwork Around a Chimney

How to calculate roof cricket (saddle) framing in 3 steps

Obstruction Width (Facing Up-Slope)The width of the chimney or obstruction as measured facing up the roof slope.

Main Roof Pitch (rise per 12)The pitch of the main roof the cricket ties into.

Cricket ridge heightThe tool computes the cricket ridge height from those figures and shows the formula, its sources, and a confidence rating alongside it.

Obstruction Width (Facing Up-Slope)	Cricket ridge height (ft)
2 ft	0.5
3 ft	0.75
4 ft	1
5 ft	1.25
6 ft	1.5
7 ft	1.75

Obstruction Width (Facing Up-Slope)

Cricket ridge height (ft)

2 ft

0.5

3 ft

0.75

4 ft

5 ft

1.25

6 ft

1.5

7 ft

1.75

Frequently asked questions

Why does a chimney need a cricket at all?

A cricket (or saddle) diverts water and debris around the up-slope side of a chimney or other wide roof obstruction, preventing it from pooling or building up ice and snow against the obstruction's back side.

Why is the ridge height based on half the obstruction width?

A symmetric cricket splits the obstruction's up-slope width into two equal sloped faces meeting at a center ridge, so each face's run is half the total obstruction width.

Does the cricket pitch have to match the main roof pitch?

This calculator assumes a symmetric cricket built at the same pitch as the main roof, which is a common approach — some crickets are built shallower or steeper depending on the roofing material and obstruction size.