Minimum

England

Minimum strap dimensions for holding down

30 mm

A strap used for holding down purposes, particularly in roof structures, must have a minimum cross-section of 30mm x 2.5mm and be at least 1000mm long to effectively resist uplift forces.

A strap used for holding down purposes, particularly in roof structures, must have a minimum cross-section of 30mm x 2.5mm and be at least 1000mm long to effectively resist uplift forces.

Basis in regulation

Part A
Approved Document A
Read the source

How to check it on site

Visually confirm the dimensions and length of any installed holding-down straps.

Common failure

Using straps that are too short or have insufficient cross-section can compromise the roof's resistance to wind uplift.

Last updated 23 August 2026. This is our editorial summary of publicly available regulation, not building control approval or a warranty determination.

Related dimensions at this stage

Minimum eaves ventilation for pitched roofs

7,000 mm

For specific pitched roof constructions, a minimum continuous eaves ventilation opening of 7000 mm²/m is a common requirement

Equivalent ventilation areas for a cold roof

10,000 mm²/m at pitched eaves; 25,000 mm²/m at low level on flat or shallow roofs; 5,000 mm²/m at the ridge

Cold roof construction with the insulation at ceiling or deck level.

Clear air gap above insulation in a cold flat or shallow roof

50 mm

Cold flat roofs and cold roofs pitched below 15 degrees.

Ventilated batten space beneath a roof underlay

25 mm

Roofs designed with a ventilated space beneath the underlay, including counter-battened details.

Minimum tile or slate width at a verge

150 mm

All verges on plain tiled, interlocking tiled and slated roofs.

Holding-down strap fixing and dimensions

30 mm

Roof holding-down straps should be 30mm x 2.5mm in cross-section and at least 1 metre long

We use cookies to keep you logged in and improve ProPlot. Privacy Policy