Practical DIY measurement before quoting
How to measure your garage door opening
If you want an indicative price before booking a survey, these are the numbers we need. They take about five minutes with a tape measure and they are the same checks our engineers run on site.
Measure the structural opening — the brick or block hole — not the existing door. Old doors are frequently fitted behind, in front of, or inside the opening, so measuring the door itself is the most common source of a wrong quote.
The five measurements
Write each one down in millimetres. Measure twice; brickwork is rarely square.
- Width: measure across the opening at the top, middle and bottom. Record the narrowest.
- Height: measure from the finished floor to the underside of the lintel at both sides and the centre. Record the shortest.
- Headroom: the clear distance from the top of the opening up to the ceiling, joist or obstruction.
- Side room: the clear brickwork either side of the opening, left and right recorded separately.
- Depth: how far back the garage runs from the opening to the rear wall.
Things that quietly change the answer
Note anything that occupies the space a door needs: a boiler above the opening, a light fitting, a loft hatch, a consumer unit on the side wall, or an internal step in the floor. Each of these can rule out a door type or require a low-headroom kit.
A floor that slopes for drainage is fine — we allow for it with the seal — but tell us it slopes so the bottom rail is set correctly.
Photos that make a quote accurate
Three photographs get us most of the way: the opening straight on from outside, the inside of the opening showing the lintel and ceiling, and one side reveal from inside. Include the tape measure in shot if you can.
Send those with your five numbers and we can give you a realistic range the same day, then confirm it at survey.
Questions we get asked
- Should I measure the door or the opening?
- Always the structural opening. The existing door may be smaller, larger, or mounted in a subframe that is coming out with it.
- What if the opening is not square?
- That is normal, particularly on older properties. Record the smallest width and height; we make up the difference with the frame and seals.
- How much headroom do I need?
- A compact roller needs relatively little, around 205 mm for the box. Sectionals need more and also use ceiling depth. If you are short on either, tell us and we will confirm what fits.
- Do I need to remove the old door before measuring?
- No. Measure the opening around it as best you can and note where the old door sits relative to the brickwork.
- Will you re-measure before manufacturing?
- Yes. Every made-to-measure door is checked on site by us before it is ordered, so your measurements are for pricing rather than production.
Send your measurements for an indicative price
Five numbers and three photos are enough for a realistic range. A free survey then fixes the figure.
Based at 31 Mount Street, Dromore (BT25) · covering Northern Ireland · 24/7 emergency repairs