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Practical guides to help you get the most from our free UK tools.
The UK voltage drop limits under BS 7671: 3% for lighting, 5% for other uses, where they're measured, why 5% isn't a hard legal limit, and a worked EV charger example.
Related tool: Voltage Drop Calculator · 3 August 2026
Real 2026 UK extension costs: price per m² for single and double-storey, regional variation, the fees and VAT everyone forgets, and a worked example.
Related tool: Extension Cost Calculator UK · 3 August 2026
How to pour a monolithic slab in the UK — the thickened-edge base for sheds, garden rooms and garages, done in one pour. Depths, mix, sub-base and a worked example.
Related tool: Monolithic Concrete Slab Calculator · 31 July 2026
How far apart floor joists should be in the UK — 400 vs 600 mm centres, how spacing affects span, and the joist size you actually need. Free calculator included.
Related tool: Floor Joist Span Calculator UK · 31 July 2026
Dry pour concrete explained for UK DIYers: how the method works, where it's fine, where it fails BS 8500 strength, a worked shed-base example, and how many bags you'll need.
Related tool: · 30 July 2026
How to work out wallpaper rolls the way UK decorators do — the drop-counting method, pattern repeat, straight vs offset match, and a full worked example. Free calculator included.
Related tool: · 30 July 2026
How deep the sub-base under a concrete slab should be, how much MOT Type 1 to order in tonnes and bulk bags, and a worked UK shed-base example. To BS EN 13285.
Related tool: Gravel Under Concrete Slab Calculator · 29 July 2026
How to calculate the dew point, why condensation and mould form on UK walls, and a worked solid-wall example with real numbers. BS EN ISO 13788 and BS 5250.
Related tool: Dew Point Calculator UK · 29 July 2026
How to work out deck and garden stairs the UK way: step count, riser height, going and stringer length, to Approved Document K. Metric, with a worked example.
Related tool: Deck Stair Stringer Calculator · 28 July 2026
How to calculate a U-value using the BS EN ISO 6946 method, the target values you need under Approved Document L, and a worked solid-wall example. UK metric guide.
Related tool: U-Value Calculator UK · 28 July 2026
How many ready-mix concrete truck loads do you need? A UK guide to mixer capacities, part-load and short-load charges, waste allowance and access, with a worked example.
Related tool: Concrete Truck Load Calculator · 27 July 2026
How many paving slabs or block pavers do you need? A UK guide to slabs per m², wastage, bedding sand and 2026 prices, with worked patio and driveway examples.
Related tool: Paving Calculator UK · 27 July 2026
How much gravel do you need? UK guide with worked examples, depth rules for driveways and paths, gravel densities and 2026 supplier prices.
Related tool: UK Gravel Calculator · 24 July 2026
Rebar weight per metre for every UK bar size, the d²/162 formula, mesh weights to BS 4483, and a worked slab example showing why you buy more steel than you calculate.
Related tool: Rebar Weight Calculator · 24 July 2026
Work out how many decking boards and joists you need for a UK deck. Board sizes, the gap that changes your count, joist centres, wastage and 2026 prices.
Related tool: Decking Area Calculator · 23 July 2026
Work out how much timber to order in the UK. Metric sizes, stock lengths, offcut waste, C16 vs C24 and 2026 merchant prices, with a worked deck frame example.
Related tool: Timber Calculator UK · 23 July 2026
What a loft conversion really costs in the UK in 2026: dormer, hip-to-gable and mansard prices, a worked example, and the costs quotes leave out.
Related tool: Loft Conversion Cost Calculator UK · 22 July 2026
How to calculate voltage drop in the UK using the BS 7671 mV/A/m method, with worked examples, the 3% and 5% limits, and the cumulative drop most people miss.
Related tool: Voltage Drop Calculator · 22 July 2026
How many screws per plasterboard sheet? A UK guide to screw spacing, quantities per board, the right screw length and lengths for walls vs ceilings.
Related tool: Plasterboard Calculator UK · 21 July 2026
How much topsoil do you need? A UK guide to working out topsoil in cubic metres, tonnes and bulk bags — with depth guidance, worked examples and 2026 prices.
Related tool: Topsoil Calculator UK · 21 July 2026
What a new driveway costs in the UK in 2026, by material and size, with a worked example, the drainage rules that catch people out, and how to compare quotes.
Related tool: Driveway Cost Calculator UK · 20 July 2026
How to calculate common rafter length from roof pitch and run, in metric, with a UK worked example, birdsmouth and overhang allowances, and the C16/C24 timber that follows.
Related tool: Rafter Length Calculator UK · 20 July 2026
Roof tiles per m² explained for UK roofs. Plain, interlocking, pantile and slate figures, the gauge maths behind them, and a worked example with real numbers.
Related tool: Roof Tile Calculator · 17 July 2026
Calculate roof pitch in degrees using rise and run. Four UK measuring methods, a worked example, and the tile thresholds that decide whether your pitch matters.
Related tool: Roof Pitch Calculator · 17 July 2026
Work out how many 25kg bags of concrete you need for slabs, posts and footings. UK worked examples, wastage allowance and a postcrete comparison.
Related tool: Concrete Slab Bag Calculator · 16 July 2026
Work out what size cable you need to BS 7671. UK worked examples for showers, garages and sockets, plus the installation methods that catch people out.
Related tool: Cable Sizing Calculator UK · 16 July 2026
How CIS tax deductions work in 2026/27: the 20% and 30% rates, what's excluded, a worked example, and the April 2026 changes.
Related tool: CIS Tax Deduction Calculator UK · 15 July 2026
Work out how much concrete you need in m³ for slabs, footings and posts. UK grades, a worked example, 2026 ready-mix prices and short-load traps.
Related tool: Concrete Volume Calculator · 15 July 2026
Work out how many sheets of plasterboard you need for a room, wall or ceiling in the UK. Real sheet sizes, a worked example, 2026 prices and a free calculator.
Related tool: Plasterboard Calculator UK · 14 July 2026
A plain UK guide to working out timber, noggins and plasterboard for a stud wall, with real 2026 costs, a worked example and a free calculator.
Related tool: Stud Wall Calculator UK · 14 July 2026
Work out how much sand and cement you need for mortar, screed and concrete in the UK, with mix ratios, bag counts and worked examples.
Related tool: Mortar Calculator · 13 July 2026
The right mortar mix ratio for UK brickwork, above and below DPC, with a mix table, lime vs plasticiser, and a worked sand-and-cement example.
Related tool: Mortar Calculator · 13 July 2026
Work out how many tiles you need for any wall or floor in the UK, with wastage, worked examples and a free tile calculator.
Related tool: Tile Calculator · 10 July 2026
The right screed mix ratio for UK floors, how much sharp sand and cement you need, plus a worked example and 2026 material costs.
Related tool: Screed Calculator · 10 July 2026
Work out how many bricks you need for a wall, garden project or extension in the UK. Includes the 60 bricks per m² rule, worked examples, and a free calculator.
Related tool: Brick Calculator UK · 9 July 2026
Learn how to calculate roof batten spacing for UK pitched roofs. Includes the formula, a worked example using standard concrete tiles, and BS 5534 guidance.
Related tool: Roof Batten Spacing Calculator · 9 July 2026
Use our concrete footing calculator UK online free to quickly estimate concrete volume, bags, and cost. Get accurate results for trench, pad, and post footings, updated for 2026 UK standards. Calculate now!
Related tool: Concrete Footing Calculator · 3 May 2026
Use our free UK weight of concrete slab calculator online to quickly determine slab weight in kg, tonnes, or lbs for your building project. Get instant results now.
Related tool: Weight of Concrete Slab Calculator · 3 May 2026