Hip & Valley

What it's for

Cutting a hip or a valley and the jacks that run into it. You give it the span, the pitch and the member sizes, and it gives you cut-ready lengths, every saw angle, the birdsmouth as cut, the jack list in pairs, a plan drawing, a cut card for each piece and a running mark-out for the jack positions. It is for a regular 90° corner with the same pitch on both sides. It does not size the members, and neither does Roof Rafter: its span check covers the commons only. A hip deep enough for the jack cuts (IRC R802.4.3) is a depth, not a size: brace it at the ridge to a bearing wall or have it designed. A valley rafter is a beam: have it sized as one, or support it at the ridge (IRC R802.4.3). In Valley mode, SIZE THE VALLEY IN BEAM SIZING opens Beam Sizing with the valley's span and load filled in.

Step by step

This example uses the numbers the screen opens with.

1 2 3 4 5 6 7

1. SCOPE — Corner works out one hip corner. Whole Roof adds a BUILDING LENGTH field and counts the whole hip roof. Scope only shows in hip mode. The example is Corner.
2. MODE — Hip or Valley. Changing it resets the corner count at the bottom of the inputs: four for a hip roof, one for a valley.
3. ENTRY — Span if you have the building width, Run if you have the run.
4. SPAN (OUT–OUT) — outside of wall plate to outside of wall plate. The example is 28' 0". It takes 2' 0" to 200' 0" (a run, 1' 0" to 100' 0"); a span past that is refused, not drawn. With Run entry the field is RUN (PLATE → RIDGE CTR) instead: outside of the plate to the center of the ridge, measured level. In Valley mode the fields read WING SPAN (NARROWER ROOF) and WING RUN (PLATE → RIDGE CTR): at equal pitches a valley runs from the inside corner to the lower ridge, so its length follows the narrower roof. Where the spans differ, a supporting valley carried on to the higher ridge is longer; work it out again with that roof's span.
   MAIN SPAN (WIDER ROOF) (MAIN RUN (WIDER ROOF) with Run entry), Valley mode only, sits under it: the other roof's span. Its jacks run from the valley up to its own ridge, so a wider main roof puts more load on the valley: a 20' wing on a 28' main roof loads it with about 70 sq ft of roof, not 50. Left alone it reads the same as the wing (an equal L). The main roof's jacks are longer: each runs the extra run further, times the slope. So with a wider main roof the jack list, the cut cards, the cut list and the order list two sets, J1 WING… and J1 MAIN…, one of each per valley, and the Jacks line in RESULTS reads, for a 20' wing at 16" o.c., 7 wing + 7 main/valley. An equal L keeps one set, cut in mirrored pairs. A note under the row says the same in one sentence.
5. PITCH — rise per 12 of run. The buttons step it by a half, from 1/12 to 24/12. Tap the number to type one.
6. To match a roof that is already there, type its slope in degrees into MEASURED ANGLE. The button beside the row then reads → PITCH; tap it and the pitch field takes the exact figure. While the row is still empty that same button reads MEASURE and opens Angle Tools, as does the line under it, MEASURE WITH THE PHONE — stand it on the stock, send the pitch. Stand the phone on a rafter or on the sheathing and send the pitch back. See Angle Tools. Either way the pitch can land anywhere from 1/12 to 24/12; past that it is limited, and a note under the row says what the reading was.
7. OVERHANG (LEVEL) — the commons' overhang, measured level and square off the plate. RIDGE THICKNESS — the ridge board. Half of it comes off each rafter's run. COMMON SEAT (PLATE) — the level seat cut of a common rafter on the plate. The hips and jacks are worked out from it. The seat is never cut deeper than a quarter of the rafter's depth, measured square to the rafter (IRC R802.7.1 and its Figure R802.7.1.1, "D/4 MAX."), so on a steep or shallow rafter it can come out shorter than you typed. The example's 3-1/2" becomes about 3-1/4" on a 2x8 at 8/12.

8 9 10 11 12

8. The member picker reads HIP MEMBER or VALLEY MEMBER to match the mode. Pick the hip or valley stock there: 2x6 to 2x12. COMMONS & JACKS is the stock for the commons and jacks, 2x4 to 2x10. JACK SPACING is their on-center spacing: 12", 16", 19.2" or 24".
9. HIP TREATMENT, hip mode only — Drop hip cuts the seat deeper so both sheathing planes land on the hip's edges. Back hip bevels the top edges instead. The results give you the other option's figure either way.
10. TAIL CUT — Plumb tail or Square tail.
11. CORNERS (VALLEYS in Valley mode) — how many identical corners or valleys you are cutting, 1 to 8. It multiplies the piece counts on the cut cards, the cut list and the materials. In Whole Roof scope the stepper is replaced by CORNERS — 4, fixed by the plan in whole-roof scope.
12. Read the answer: Hip ≈ 21' 9-1/2".

In Valley mode the span rows change. This is a 20' wing on a 28' main roof, the numbers the carry below uses.

4

Reading the results

13 15 16 17

14

13. The headline is the hip or valley length, ready to cut. The first line under the button says how: cut-ready — long point at ridge → heel, along the top edge. The ridge has already been taken off. In Whole Roof scope the headline is the ridge length, and the first line says it is theoretical: the building length less the span, hip to hip centres. Cut the board to fit at the hips. The hip comes next, then the counts of commons, hips and jacks and the roof area. The counts are the pieces in the roof; the sheathing line gives the sheets the roof covers and, beside them, the order with Roof Rafter's 10% waste. The next line says what the member is not. In Hip mode: Hip 2x10: depth for the jack cuts (R802.4.3), not a size — brace at the ridge to a bearing wall or have it designed. In Valley mode: A valley rafter is a beam — size it, or support it at the ridge (R802.4.3). The cut sheet prints the same line. In Valley mode one more line says what the Beam Sizing button carries: the valley's span in plan (≈ 14' 1-11/16" in the example), and a tributary width that loads it as evenly as the jacks do at its worst point (≈ 5' 0-3/16"; the jacks on both sides put more load near the eave than the ridge), with both roofs' jacks counted. It says the carry is on posts and that the ground snow is still to set there. The line ends with the share the post at the ridge end carries: a third on an equal L, more when the main roof is wider (38% for the 20' wing on a 28' main roof).
14. SIZE THE VALLEY IN BEAM SIZING, Valley mode only, sits first in RESULTS, above CAP AND LINE IT IN ROOFING and CUT DETAIL. It fills in Beam Sizing's SPAN and TRIBUTARY WIDTH, sets LOAD TYPE to Roof and SUPPORT to On posts (a valley bears on the wall plates at the corner and on a post at the ridge, never in a wall), then opens it. GROUND SNOW comes from Roof Rafter when you have picked one there; otherwise it is left unpicked and Beam Sizing says in amber Set the ground snow for this roof. Your species and material there stay as you left them.
15. CAP AND LINE IT IN ROOFING opens Roofing with the hip or valley length filled in — the edge on the roof surface from the ridge to the eave edge, overhang included, which is what the cap and the valley lining run. It is longer than the framing hip above, which stops at the plate and the ridge. Hip mode fills HIP LENGTH with every hip (four on a whole roof); Valley mode fills VALLEY LENGTH, and PITCH is set to this roof's pitch. Everything else in Roofing stays as you left it.
16. CUT DETAIL + JACK LIST opens the cutting page: the hip in elevation with its birdsmouth enlarged, a cut card for each piece that you swipe through, a button into Angle Tools with this roof's angles loaded, and the jacks listed in pairs, longest first. The cards are described below.
17. The lines. The rise at the center and the height of the ridge top above the plate. Plumb, Level and Bevel for the hip. Drop or Back, with the other option in brackets. The hip birdsmouth as cut: seat, heel and HAP, with the drop already in it. The common rafter's length, plumb angle and HAP. Jacks: the difference in length from one to the next, pairs per corner, miter and bevel. The tail: the projection to the long point, and the distance from the bottom point to the heel along the stick. The sheathing angle for the sheets that land on the hip.
18. BASIS & WHAT WAS ASSUMED — tap it. It lists exactly what was deducted from the commons, the hip and the jacks for the ridge and the hip thickness, so you do not deduct twice. It says how the drop or backing was applied, and that the numbers are for a regular 90° corner with equal pitches. When the seat you typed would notch the commons more than a quarter of their depth, BASIS says it was cut shorter, and to what.
19. BASIS also says what is not checked: the loads are gravity only, so where IRC R301.2.1.1 requires wind design, or in Seismic Design Category D0 to E (R301.2.2; townhouses from C), the added rules are not applied. Nor are the uplift ties at each rafter seat sized (IRC R802.11).

Every result carries two birdsmouth lines. The first is the commons' and jacks' seat, cut to the quarter-depth limit. It is green when that seat still bears at least 1-1/2" on the plate (IRC R802.6). It is red when it does not, and then it says what to do: cut a longer seat, or use a deeper common if the quarter-depth limit is what keeps it short (a 2x4 at 12/12 can only take about 1-1/4"). The second line is the hip or valley's own seat. That seat is set by the roof plane, not by you: the hip has to sit at the commons' height above the plate, so a hip deeper than the commons notches deeper. Over a quarter of its depth, it is red. Hip seat notches 40% of the 2x10 to stay in the roof plane — over the D/4 IRC R802.7.1 allows; carry the hip end on a post at the corner, or have it designed is what the example shows. A hip deep enough for the jacks' cut ends (below) almost always seats deeper than a quarter, so expect this line on a sawn hip or valley: plan a post under the corner, or have the hip designed.

In Corner scope three more red lines can appear. Hip member too shallow for the commons' plane — verify size (or Valley) means the member's whole depth does not reach the commons' roof plane, so it cannot be seated to it: pick a deeper member. No seat line is given for it, since it has no seat to judge. A deep hip on shallow commons is not "too shallow"; its seat is just deeper, and the seat line above judges it. Hip 2x8 is 7-1/4" deep — under the jacks' 8-11/16" cut end means the hip or valley is shallower than the jacks' plumb cut, which IRC R802.4.3 does not allow: go one size deeper. Under 3:12 the ridge, hips and valleys must be designed as beams appears below 3 in 12 (IRC R802.4.4). Then every surface treats the hip or valley as a designed beam, not sawn stock: the member line, the materials and the cut sheet say so, the cut detail is titled Hip Beam Detail (Valley Beam Detail for a valley, with DESIGNED 2.5/12 in its strip at that pitch), there is no cut card for it, Angle Tools offers no cut for it, and no seat-notch line is given for it. Nothing gives it a sawn birdsmouth either: RESULTS has no cut-ready, drop or birdsmouth line for it, BASIS says only the commons and jacks are cut-ready, and the Beam Detail draws the member with a straight bottom edge, no seat, heel or drop, and BEARING + CONNECTION BY THE DESIGNER at the plate line. At 3:12 and steeper all of them come back. In Whole Roof scope two check lines show, Building length ≥ the span and Common span within the table, green when within the limit. The first turns red if BUILDING LENGTH is not longer than the span, because a square plan is a pyramid with no ridge. The second turns red if the commons' span is off the table. Size them in Roof Rafter.

The cut cards

On the Cut Detail page, under CUT CARDS — SWIPE FOR EACH CUT, there is one card for each different piece: the hip or valley first, then the common, then every jack. Each card is a board drawn with its long-point length, the plumb-cut setback and the birdsmouth station, a title strip, and the marks in the order you make them. The head cut at the ridge end is labelled with the angle it is struck at: PLUMB 25.2° · DOUBLE 45° CHEEK on the hip or valley card, PLUMB …° · SIDE CUT 45.0° on a jack card, and the plumb angle alone on the common. The badge at the top right of the card is the count for the whole job:

• The hip or valley card reads CUT 4 in the example — one per corner, so the number is the CORNERS (VALLEYS) count.
• The common card reads REFERENCE CUT. It is there for the angles, not for a count.
• A jack card reads CUT … TOTAL · 2 PER CORNER (per valley in valley mode): the total across every corner, and the pair at each one. When there is one corner it reads plain CUT 2. A green line under the marks says 1 RIGHT + 1 LEFT per corner — offcut is the opposite hand.

Under the cards, JACKS — ONE CORNER · CUT IN PAIRS · LONG POINT, TAIL INCL. lists each jack with its pair count, its length and its miter and bevel. The length is the same one the card and the cut list print: to the long point of the cheek cut, tail included (a valley jack has no tail). The line under the list: Pairs land opposite across the hip — offcut is the opposite hand. Nail the center pair first to hold it straight. In valley mode the jacks have no plate, no birdsmouth and no tail, and their cards say so. For the bevel screen and the printed template, see Angle Tools and cut cards.

20 21 22

20. The drawing is the corner in plan: plates, hip, ridge and every jack at its spacing, with the run and the spacing dimensioned. In Whole Roof scope it is the whole roof. Pinch to zoom, drag to pan, double-tap to reset. The expand button opens it full screen. See Reading the drawing.
21. RUNNING MARK-OUT gives the position of every jack as a running tape, so you hook once and mark down the stick. Each jack has two figures, its near face and its far face. RUNNING HIP is the tape up the hip. PLATE is the tape along the wall plate from the corner. In valley mode the tapes are RUNNING VALLEY and RIDGE, because valley jacks touch no plate. The line under the list says where to hook.
22. The speaker reads the marks aloud. See Mark-out and speak.

Under the mark-out, MATERIALS lists the stock. The hip or valley row gives the stock length, then the length you cut, tail included, with the ridge-to-heel length in brackets. The Jacks row counts the jacks and lists the sticks to buy by length. Each rung is bought by its own length, and where both hands of a rung fit end to end in one stick (24' at most) they share it. Hurricane ties gives one per hip and jack seat (one per valley seat); IRC R802.11 allows Table R602.3(1) toe-nails instead only under its exceptions. The commons' ties are in Roof Rafter. 16d box nails rows give the connections from Table R602.3(1) item 7: four toe-nails at each jack's hip or valley end (a valley jack also at the ridge) and four per hip at the ridge. In Valley mode, Valley-to-ridge hanger (designed): a valley is a beam, so carry its ridge end on the brace post or on a hanger rated for the load Beam Sizing gives (IRC R802.4.3, R802.11.2). Ridge brace posts is one post at the ridge end of each hip or valley, down to a bearing wall (two in Whole Roof scope, one where each pair of hips meets the ridge); cut them to fit and size them for the load, or have them designed. At the bottom, CUT SHEET, the list icon at its right end, CUT LIST, SEND LIST and OPTIMIZE stay dim until you change at least one input. SAVE stays lit, but while every input is still a default a tap only answers Enter your job's numbers first and saves nothing. CUT SHEET makes a PDF with the cut detail drawing; its MATERIALS are the same rows as the screen's, stock lengths and hardware included, followed by CUT LIST, each piece at the length the saw cuts. The material-list-only PDF prints the same list. SAVE keeps the result in History, CUT LIST puts the hip and each jack pair on the Lock Screen, SEND LIST sends a checkable list to another phone, and OPTIMIZE sends the jacks, at their full length with the tail, to the Cut List Optimizer. While a cut list from this screen is running, the piece you are on shows green in the plan and in the jack list, and the cut cards open on it.

Common mistakes

• Deducting for the ridge again. The lengths are cut-ready. Open BASIS & WHAT WAS ASSUMED to see what has already come off.
• Measuring from the wrong point. Lengths run along the top edge, from the long point at the ridge to the heel of the seat cut. The tail is given separately.
• Reading a jack card's total as the count for one corner. The badge is the whole job. The per-corner pair is after the dot, and the green hand line says one right and one left.
• Typing a run into the span field. Check ENTRY first. A run entered as a span gives a roof half the size.
• A different seat on Roof Rafter. COMMON SEAT (PLATE) sets the height above the plate for everything here. Use the same seat on both screens for the same roof.
• Using it for an odd corner. The numbers are for a 90° corner with equal pitches.
• Taking a green span check as the hip or valley's size. Roof Rafter's check is for the commons. A valley carries the jacks on both sides like a beam, and a hip needs its brace at the ridge.

Related

• Roof Rafter — commons, ridge and the span check
• Roofing
• Beam Sizing — a valley is a beam; SIZE THE VALLEY IN BEAM SIZING carries its span over
• Angle Tools and cut cards
• Mark-out and speak
• Reading the drawing
• Cut sheets and 1:1 templates
• Cut list on the Lock Screen
• Send to the Cut List Optimizer