Measuring & Marking
Laser levels, optical levels, and marking gauges - the tools that turn rough guesswork into accurate layouts on a construction site.
The difference between a professional-looking finish and a bodged one usually comes down to how carefully things were measured and marked before any cutting or fixing started.
These guides cover the levelling, setting-out and marking tools you will meet during a UK extension project. Whether you are checking that the foundations are at the right level, marking socket heights on a wall, or setting out kitchen units, the right tool makes the job faster and more accurate. Each page explains what the tool does, when you need it, and what to buy at each budget tier.
Where to start
Read profile boards before anyone digs. They are how the footprint of the extension is set out, and the guide lists the checks to make while mistakes are still cheap. Then read the laser level guide: a cross-line laser is the most useful measuring tool a homeowner can own for checking unit heights, tiling lines and socket positions. The optical level guide explains how site levels for foundations and drainage are taken, and when to pay a surveyor instead.
The guides, grouped by job
Setting out and site levels. Profile boards, the optical level and levelling staff, the rotary laser level with a laser detector for reading the beam outdoors, and the water level for carrying a level around corners and obstructions.
Indoor lines and distances. The cross-line laser level and the laser measure, with the guide explaining when a tape still wins.
Marking timber for joinery. The marking gauge, cutting gauge for cross-grain lines and mortice gauge. These matter most if you are doing joinery work yourself.
Where these fit in the build
Profile boards and site levels belong to setting out, foundations and footings and drainage. The laser level comes back for kitchen installation and the snagging checklist.
Cutting Gauges: Why a Blade Beats a Pin When Marking Across the Grain
The UK guide to cutting gauges for joinery shoulder lines and cross-grain marking. How to set the blade, when to use one over a pin gauge, and what to buy from £16.
Laser Detectors: How to Use a Laser Level Outdoors When You Can't See the Beam
The UK guide to laser detectors (laser receivers). How they extend laser level range outdoors, how to clamp one to a staff, and what to buy from £30.
Laser Levels: Green vs Red, What to Buy, and How to Actually Use One
The UK guide to cross-line laser levels. Green vs red, self-levelling explained, calibration checks, and what to buy from £40 – £56 upwards.
Laser Measures: Why a £40 Distance Tool Replaces Your Tape for Most Jobs
The UK guide to laser measures (laser distance meters). Range, accuracy, area and volume calculations, what to buy from £40, and when a tape measure still wins.
Levelling Staffs: How to Read the E-Pattern Graduations and Take an Accurate Reading
The UK guide to levelling staffs (telescopic surveying rods). How to read the graduations, set up properly with an optical level, and what to buy from £50.
Marking Gauges: Pin vs Wheel, Types, and How to Scribe a Perfect Line
The UK guide to marking gauges. Pin vs wheel, mortice vs cutting, how to use one properly, and what to buy from around £8 upwards.
Mortice Gauges: Setting Two Pins for Mortise-and-Tenon Joints That Actually Fit
The UK guide to mortice gauges for traditional joinery. How to set the two pins to a chisel width, how to scribe shoulder lines, and what to buy from £18.
Optical Levels (Dumpy Levels): How to Set Site Levels for Foundations and Drainage
The UK guide to optical levels for extension groundworks. How to read the staff, take backsight and foresight readings, hire vs buy, and when to pay a surveyor instead.
Profile Boards (Batter Boards): How to Set Out an Extension Footprint
The UK guide to profile boards for setting out an extension. What they are, how the lines come off for the dig, the 3-4-5 square check, and the four things to check before anyone digs.
Rotary Laser Levels: How to Set Foundation and Drainage Levels Across a Whole Site
The UK guide to rotary laser levels for groundwork. How they differ from cross-line lasers, hire vs buy decisions, and pairing with a detector and staff.
Water Levels: Why a £15 Hose Beats a £400 Laser Around Corners
The UK guide to water levels for transferring levels around obstructions. How they work, when to use one over a laser or optical level, and what to buy from £10.