Load path and footings
Trace an addition's weight from the roof to the soil, and size the pad that catches it.
AdditionsStructureIRC Table 401.4.1
Planning tools
Four calculators we use on every site walk
These are not lead magnets. They are the four pieces of arithmetic that decide whether a renovation is straightforward or structural, and we would rather you ran them before you called us.
4 tools2021 IRC and 2023 NECFree, no sign-up
Basement egress and moisture
Check an opening against the five code numbers, and read what the water is doing.
Basements2021 IRCEgress and moisture
Floor height and transitions
Stack up the subfloor, underlayment and finish before you order, not after.
FlooringSubfloor prepTransitions
Electrical service capacity
Run the NEC optional calculation and find out whether 100 amps still carries the house.
Whole-homeNEC 220.82Service upgrades
Try one here
Basement egress and moisture check
Measure the actual clear opening with the window wide open. Six dimensions have to be satisfied at once for a basement sleeping room.
This opening would serve a basement sleeping room
All six dimensions are met and the well is shallow enough that no ladder is required. Drain the bottom of the well to the perimeter drain regardless.
The six numbers
Net clear opening5.7 sq ft minimum6.00 sq ft
Opening width20 in minimum36 in
Opening height24 in minimum24 in
Sill above finished floor44 in maximum42 in
Window well area9 sq ft minimum12.00 sq ft
Well projection36 in minimum36 in
Permanent ladderRequired when the well is deeper than 44 inNot required
Water reading 0 of 4
Nothing checked. Even a basement with no visible water needs a capillary break under new framing and continuous insulation against the concrete, because concrete moves moisture as vapour whether or not it ever looks wet.
Based on the 2021 IRC as commonly adopted in Montana. Confirm current requirements with the City of Bozeman or Gallatin County before you order a window.
And another
Floor height and transition planner
Stack the layers in two rooms and see what the doorway between them is going to need.
1/8 in higher in room ADifference in finished floor height at the doorway
The stack, layer by layer
- Room A total build-up
- 1 1/2 in
- Room B total build-up
- 1 3/8 in
- Clearance left under the door
- 1/2 in
Bevelled reducer
A shop-made reducer with a shallow bevel carries this difference without a trip edge. We cut it from the same stock as the higher floor so it reads as part of the floor rather than as a strip.
1/2 in of clearance under the door. No undercutting needed.
Before any of this matters, the subfloor has to be flat: 3/16 in over 10 ft for most wood products, 1/8 in over 10 ft for large-format tile. And the floor has to meet L/360 deflection, or L/720 for natural stone.
These are planning figures, not designs
Every one of these tools is accurate enough to tell you which kind of project you have, and none of them replaces a licensed professional. Structural work gets an engineer's stamp. Electrical work gets a licensed electrician. Code references reflect the 2021 IRC and 2023 NEC as commonly adopted in Montana, and your building department is the final word.
