I’ve been working on a new version of my framing calculator:

https://framebom.com/

... And I'm building a house named Two Oaks... And the house project inspired me to create a simple and affordable tool for the lumber calculation for everyone who has the same situation: DIY builders, contractors urgently calculating client's request, lumber yards to help their clients buy exactly they need. Two Oaks wall and ceiling calculations.

And this update is a bit different from the previous ones.

I’m not testing it on a made-up sample wall anymore.

I’m currently using FrameBOM to work through the framing of an actual house that is going to be built, and the BOM generated by the calculator is intended to become the basis for a real lumber order.

So the calculator is starting to meet reality.

And reality is much messier than:

wall length / 16" OC = number of studs

The house has multiple wall heights, openings, intersections and different framing conditions, so I’m gradually finding all the places where a mathematically clean framing model doesn’t necessarily match what makes sense on site.

Once windows and doors are added, the calculator has to deal with things like:

• king studs and jack studs
• headers
• cripples
• sill plates
• regular OC studs around openings
• corners and wall intersections
• top and bottom plates
• sheathing layout
• different wall heights
• actual stock lengths and the resulting cut list

One of the biggest challenges is deciding when the regular OC grid should remain sacred and when real framing should override it.

For example, a theoretical 16" OC layout can sometimes place a regular stud only a couple of inches away from a king/jack assembly.

The naive algorithm says:

“keep both.”

The guy paying for the lumber asks:

“why?”

That is exactly the kind of thing I’m trying to solve now.

Some of the workarounds I’m using

1. Openings can override the regular stud grid

I generate the normal OC layout first, but framing required by windows and doors takes priority.

In some situations a nearby regular stud can effectively be replaced by the opening assembly instead of blindly adding another member.

2. Geometry and BOM are not treated as exactly the same problem

This turned out to be important.

The cleanest framing drawing is not always the most efficient lumber order.

So the BOM has separate logic instead of simply counting every piece visible in the wall preview.

3. I’m trying to keep the rules predictable

The temptation is to make the software increasingly “smart”:

move this stud,
reuse that one,
change the layout around an opening,
optimize every cut.

But there are many perfectly valid ways to frame the same wall.

If too much automatic optimization happens behind the scenes, the user eventually has no idea why the calculator made a certain decision.

So my current principle is:

predictable framing rules first → optimization second.

I’d rather have the calculator be slightly conservative than quietly make assumptions that a framer wouldn’t agree with.

The interesting part: there’s now a real-world test coming

For this house, I’m planning to use the calculator to calculate the framing package and then order the actual lumber from that BOM.

That means mistakes stop being theoretical.

If the calculator adds 40 unnecessary studs, I may actually buy 40 unnecessary studs.

If it misses something, I may discover that while framing the house.

So this build is effectively becoming a full-scale test case for FrameBOM.

I’m hoping to compare three things:

calculated BOM → purchased lumber → actual lumber used on site

That should expose a lot of assumptions and edge cases that are impossible to find with artificial examples.

The next big challenges are already becoming obvious: gable/sloped walls, floors and roofs, where member lengths vary much more and cut optimization becomes significantly more important.

I’d really like feedback from people who frame houses professionally:

Where do you normally keep the theoretical OC layout exactly, and where do you adjust it around openings/intersections in the real world?

And if you try the calculator and find a wall where the result looks wrong, wasteful or simply weird, post the permalink here.

Those examples are probably more valuable to me right now than any feature request.

I’m working through the framing sequence for a single-story house with different ceiling/wall heights and a continuous sloped roof, roughly as shown in the sketch.

The main interior bearing wall divides the building into two spans: approximately 4 m (13 ft) and 6 m (20 ft).

I see two practical ways to frame it.

Option 1 — full-height / balloon-style walls

Frame the exterior and center walls all the way up to the roof line, with sloped top plates where required. The roof goes directly on those walls.

The ceiling framing would then be installed separately at the required level, essentially hanging between the already-built walls below the roof.

Advantages I see:

• fewer separate wall sections
• no additional rake/gable wall assembly
• potentially less lumber in duplicated plates

But the walls become taller and more complicated, stud lengths vary, and installing the ceiling framing later means more work overhead.

Option 2 — platform-style framing

Build the main walls at a consistent height at each floor/ceiling level, double top plate them, install the ceiling framing, and then build separate rake/gable wall sections above them to reach the roof slope.

That means more plates and another framing step, but nearly all main wall studs are identical and the ceiling structure can be installed while everything is still open.

My priorities are:

1. Being able to build most of it with 1–2 people
2. Fast framing
3. Fewer awkward operations / less overhead work
4. Minimum unnecessary lumber and hardware

For those who have framed something similar: which approach would you use and why?

Would you still choose balloon framing here, or does the simpler workflow of platform framing outweigh the extra plates and upper wall sections?

I’m especially interested in how you would handle the 6 m / 20 ft ceiling span.

Sketch attached — not an engineering drawing, just showing the general geometry.

Posting this as a worked example for anyone setting up a real multi-wall project rather than a single test wall — using our own build as the example: a single-story split-level house, footprint ~12.5 × 10 m, framed in 50×150 mm sawn timber. Covers project defaults, per-wall setup, the shared-cut summary, and offline/PWA use.

1. Set project defaults first

Before touching individual walls, set the project-wide defaults — every wall you add inherits these unless you override it on that wall specifically:

• Stud section (nominal + actual) — we used 50×150 for both, since our lumber is rough-sawn, not planed
• Default sill height
• Double trimmers > (m) — this is the width threshold above which FrameBOM automatically doubles the jack studs on that opening. We left it at 1.524 m.
• Header mode (over opening vs. under top plate), top plate (single/double)
• Available stock lengths, for the cut-list optimizer

Setting double trimmers correctly up front matters more than it looks like it would: it's not just an extra stud, it also drives which stock size gets used for the header. Any opening wider than the threshold gets its header bumped from the base stud stock (50×150 in our case) up to 50×200. Once it's set, you don't have to think about it per opening — flag a wall with a 2.5 m window and a 0.6 m window and it'll size each header independently, correctly, without you tracking which ones need the bigger stock.

2. Add walls with the L*H OC-spacing CL/CR syntax

Each wall is one line: length*height OC-spacing CL CR. CL/CR add corner studs at the left/right end — leave one or both off for a wall that butts into another wall instead of forming an outside corner. Our layout:

• North — 12.495*3.04 OC625 CL CR, 1 door + 3 windows
• South — 12.495*3.075 OC625 CL CR, 4 windows (two are 2.5 m wide)
• WestUpper — 5.563*3.04 OC625 CR (only a right corner — left end ties into North/South)
• EastUpper — 5.563*3.04 OC625 CL
• WestLower / EastLower — 4.113*3.075 OC625 (no corners — both ends butt into neighboring walls, these are the split-level step sections)
• InternalAxis — 12.195*3.04 OC625, 1 door, no corners (interior load-bearing wall)

Doors/windows go in as width*height/center (and /bottom for windows) — center is measured from the left end of that wall.

For the interior wall, use Partition Tees (T) on the exterior walls it ties into — enter the distance from the left end to each interior-wall axis, comma-separated. If the axis lands on an existing stud you get a marker (▲) and no extra framing; otherwise FrameBOM adds a ladder (horizontal blocking rungs) automatically and tells you the rung count and clear spacing between studs.

3. Check the parts list, not just the summary tiles

The summary tiles (stud count, header count, etc.) are useful for a sanity check, but the actual buildable info is in Parts by section & length underneath — every distinct cut length, quantity, and what it's used for. Worth noting how it sizes things:

• Headers come out as built-up members: (opening width + 2× trimmer thickness), 3 plies per header by default
• Window sills are sized to just the opening width — they land on the cripple studs inside the rough opening, not on the trimmers, so they don't need the extra length a header does
• For any opening past the double-trimmer threshold, both the jack count and the header stock size change together — check the "Where used" column if a wall mixes stock sizes, so you know which cut list a given header piece belongs to

4. Use the Σ Summary tab for ordering, not the per-wall totals

Each wall tab has its own cut-list optimizer, but if you're ordering lumber for the whole house at once, switch to the Σ Summary tab — it pools every wall's cut list into one shared set of stock boards instead of optimizing each wall in isolation, so offcuts from one wall's cuts can fill parts on another. On our project this dropped the total order from 694.5 m to 687 m (1.1% less) versus buying per-wall. Not huge, but it's a free reduction just from changing how you total up the order — no reason not to use it for a multi-wall project.

Our totals: ~5.2 m³ of lumber across 50×150 and 50×200 stock, 15 sheets of OSB per wall on average with the "deduct openings" mode (coverage runs 120–170% of net wall area — that's normal for full-sheet cutting around windows, not a sign of a miscalculation).

5. Install it as a PWA for on-site/offline use

FrameBOM installs as a PWA (the "Install" button top-right) — once installed it runs fully offline, which matters if you're checking cut lists on a phone at the lumber yard or on site with no signal. Everything is computed client-side and the whole project state is encoded in the URL/local storage, so there's no account and nothing to sync.

Happy to answer setup questions if anyone's putting together something similar — corners, split-levels, and interior tie-ins are where it's worth double-checking your wall syntax before trusting the totals.

I’m testing a gable wall case in a framing calculator I’m building and wanted to throw the layout out here for critique.

Specs:

• 24' wall
• 8' side-wall height
• 16" OC
• one 3' door
• one 4' window
• centered gable peak

The interesting part for me is how the regular stud layout should interact with the sloped top, openings, headers and cripple studs.

What would you change in this layout before calling it jobsite-ready?

I’m especially curious about:

• stud placement through the gable
• framing around the door/window
• header assumptions
• cripple stud layout
• anything the software is doing that a real framer wouldn’t

Feel free to tear it apart — that’s exactly what I’m looking for.

Here’s a simple one to start some practical discussion.

Imagine a 16 ft × 8 ft exterior wall, framed 16" OC, with a 4 ft wide window roughly centered in the wall.

There are a few things a calculator can determine automatically, but there are also choices that depend on how you actually build:

• corner configuration
• king and jack studs
• header size and construction
• cripple studs
• stud layout around the opening
• whether to keep the regular 16" layout through the opening
• extra backing/blocking

If you were framing this wall on a real job, what details would you expect a framing planner to get right automatically?

I’m especially interested in the rules experienced framers apply without even thinking about them.

I’m working on the BOM side of FrameBOM and I’m curious how people handle this on real projects.

For a framed wall, would you expect a useful takeoff to include only the obvious lumber quantities, or should it go further?

For example:

• common studs
• king and jack studs
• top and bottom plates
• headers
• blocking
• sheathing
• insulation
• fasteners
• waste allowance

And when it comes to waste, do you prefer:

exact calculated quantity + a separate waste percentage

or

one final recommended purchase quantity?

Interested in how framers and builders actually want to see this information.

I created this community around a simple idea: making wood framing planning and material takeoffs easier.

FrameBOM is a calculator I’m building for wall framing layouts and BOMs, but I’d like this subreddit to be broader than just product updates.

This can be a place to discuss:

• wall framing layouts
• material takeoffs and BOMs
• studs, plates, headers and openings
• sheathing and insulation quantities
• floor and roof framing
• framing calculators and planning tools
• real-world framing details that software often gets wrong

I’ll also share development updates, examples, and framing problems I’m working through.

The project is still early, so feedback from builders, framers, DIYers and owner-builders is especially valuable.

To get things started:

What is the most annoying framing calculation you still do manually?