Peak Cap Reference

Find the slope, pick your path, set the saw. For a light dead center at the peak.

What did you measure with?

Reading

Your saw tilts to

31.0°slope · about 7/12

PATH A perpendicular · on the jig

Example loaded: a 31° roof. Type your own reading. Every dial is counted from square (0°).

Step 1Find the slope

Speed square + level

Always reads from level.

Slope = the reading

Digital gauge

Set it flat on something level first. 0.0 means it reads from level. 90.0 means it reads from vertical.

0.0: slope = reading
90.0: slope = 90 − reading

Johnson across the peak

Measures the whole peak (apex). Over 180°? Apex = 360 − reading first.

Slope = (180 − apex) ÷ 2

Gut check

Houses run 18° to 45°. A reading over 45° on a normal-looking roof means the gauge read from vertical: use 90 − reading.

Same width, two slopes. Look up at the house: which one is it?

Step 2Pick your path

Path A · perpendicular, on the jig

Slope under 45°. Most roofs.

Path B · parallel, along the fence

Slope 45° or more. Steep roofs.

Why the split: along the fence the saw has to tilt to 90 − slope. On a 31° roof that’s 59°, past most saws, so it goes on the jig.

Same cut, two setups. The cap angle is always the slope; the saw reads from square.

CutsThe 9 cuts

Cuts 1–5 · the cap (peak cap channel)

Ribbed edge down, the way it installs. Start at the end of the channel.

Cuts 6–9 · the tracks (light track)

Center track top edge = L, the cap’s ribbed part. Every track cut is half the slope, long point on top.

Path APerpendicular, on the jig

Jig on the fence. Channel end on the fence, ribbed edge tight to the jig.
Dial the slope. Cut 1.

Jig off. Cut 1 edge flat on the fence.
Dial 90 − 2 × slope, swung the other way. Blade on the point. Cut 2.
Cuts 3 and 4: 45°, back in. Cut 5 optional. Cuts 6–9: slope ÷ 2.

Flatter than 5/12 (under 22.5°)? Cut 2 needs more than 45°. A 4/12 roof needs 53°. Ask before cutting.

Path BParallel, along the fence

Open edge on the fence, ribbed edge toward you. Start at the end of the channel.
Dial 90 − slope. Cut 1.
Same number, swung the other way. Blade on the point. Cut 2.
Cuts 3 and 4: 45°, back in. Cut 5 optional. Cuts 6–9: slope ÷ 2.

FitFit the peak

Cap only: two tabs, one screw each straight up into the home. Level under the bottom.

Add the center track and rake tracks. Lights: center first, then down each side.

Peak cap with a screw tab at the bottom corner

Screw tab, bottom corner: every peak.

Peak cap with a bracket on each top slope

Bracket on each top slope: bracket installs only. The screw tabs still go on.

Dry fit first. Cap, center track and both rake sticks go up dry. Lights go in only when every joint closes.

OnceBuild the jig

A 4×4 block with a metal plate screwed to one end. The plate hooks the fence edge; the channel’s ribbed edge rests on the block’s other end, so the blade comes up through the top of the ribbed part.

Cut a straight 4×4 a little long.
Screw a metal plate to one end so it overhangs and hooks the fence edge.
Measure from the fence edge to where the blade crosses the top of the ribbed part. Cut the block to that length.
Lower the blade (unplugged). Hits the ribs? Shave the block. Gap? Shim the end.
Mark it PEAK JIG · DO NOT CUT.