Stage 1 · Project
What are you walling, and with what?
Pick the wall type first. Everything else in this calculator — thickness, mortar, ring beam width and wall ties — follows sensible defaults from this choice, and you can adjust the ones that genuinely vary from site to site.
How will you measure your walls?
You can switch later without losing or changing the real dimensions.
Metres
Feet
Wall type
Calculate from the actual masonry-unit face size Use the supplier's measured length and height plus the mortar joint instead of a general units-per-square-metre allowance.
Boundary: this tool covers blocks/bricks/stone, mortar, openings deduction, a continuous ring beam, DPC and wall ties — the walls and ring beam only. Plastering is the separate Plastering Calculator, and roofing is the separate roofing calculators.
Wall sections
Stage 2 · Wall sections
How long and how high are your walls?
Most simple rectangular houses only need one row: the total length of every wall, and the height from the top of the slab to the underside of the ring beam. Add more rows for a gable end, a stepped plot, or a feature wall that is a different height.
Wall section Use Shape Length (m ) Height / rise (m ) Other end RB DPC
+ Add another wall section
Shapes: use Rectangle for normal walls. Add a separate Triangle row for a gable above its rectangular wall. Use Trapezoid where the two ends have different heights. Ring beam and DPC are counted only on rows you tick.
Back Openings
Stage 3 · Openings
Doors and windows reduce the wall you need to build.
Enter each door or window size once, with how many of that size you have. Their combined area is subtracted from the wall before counting blocks, bricks or stone, and before working out mortar.
Wall section Type How many Width (m ) Height (m ) Lintel
+ Add a door or window size
Lintels over openings
Leave this empty if you would rather work from a blank-wall estimate first — you can always come back and add openings before you unlock the full result.
Back Ring beam & DPC
Stage 4 · Ring beam & DPC
The concrete band that ties the walls together, and the damp course beneath them.
Ring beam is a continuous reinforced concrete band cast on top of all the walls at once — not a separate lintel over each door and window — so its length is your whole wall perimeter, and it does not shrink because of openings below it.
Ring-beam formwork
Ring beam steel
Use the structural drawing. Main bars and links/stirrups perform different jobs, and their diameter, count and spacing must come from the engineer's ring-beam detail. The rows below only convert that approved detail into stock bars and cost.
What is it? (e.g. main bars, stirrups) Bar size How many Length of each (m ) Length you buy (m )
+ Add another bar line
Damp proof course (DPC)
DPC is the waterproof strip laid along the top of the wall base, at the point the walling begins above the slab, so damp cannot rise into the walls above.
Back Ties & waste
Stage 5 · Wall ties & waste
A few last quantities before pricing.
Include wall ties Ties (sometimes sold as hoop iron) key a block wall into the concrete columns of a framed building so it cannot crack away from the frame. Ticked by default for block walls; untick it for a wall that is not built between columns.
Procurement allowance
Back Rates
Stage 6 · Local rates
Use prices from your supplier and site.
Enter prices from your local supplier, fundi, contractor or quarry. The calculator does not assume that Nairobi prices apply to your site.
Use local rates only. Enter the actual unit price beside every applicable item. Enter 0 only where an item genuinely has no cost for this project.
Steel price per 12 m stock bar
Back Review
Stage 7 · Review and unlock
Check the inputs before pricing.
Nothing below reveals cost. Confirm your wall sections and openings, then unlock the full walling breakdown.
Your calculation is ready. No quantities or costs are shown before payment. Unlock below to generate the complete walling BOQ and PDF.
Back Prepare full estimate