How do I fix a gate that drags or will not shut?

Diagnosing whether a gate has dropped, the post has moved, or the timber has swollen — and fixing each.

Difficulty: intermediate
Time: 1 hr 30 min
Read: 2 min
Safety: caution

Short answer

Check the post first by pushing it — movement at the base means the post has rotted or its concrete has failed, and no amount of adjusting the gate will help. If the post is solid, the hinges have dropped or the timber has swollen seasonally.

Gates drag for the same reasons doors do, with weather added. Almost always it is the post rather than the gate, because a gate post takes a constant sideways load and sits in wet ground.

Safety

Check for buried services before digging any post hole. Gates are heavy and awkward — get help lifting one off its hinges. If a gate is on a boundary, establish who owns it before altering it.

What you'll need

Spanner and screwdriver
Spirit level
Spade
Concrete repair spur (optional)
Postcrete (optional)
Plane or surform (optional)

Step by step

Push the hinge post firmly and watch the base.Any movement means the post is the problem, and adjusting the gate will achieve nothing.
Test the post at ground level with a screwdriver.If the point sinks into the timber, it has rotted and needs replacing or supporting.
For a rotted post, fit a concrete repair spur bolted to the sound upper section.Far less work than digging out the whole post and its concrete.
If the post is sound, check the hinge fixings.Gate hinges take a large load and the screws work loose. Longer coach screws into solid timber are the fix.
Adjust adjustable hinges if fitted, a small amount at a time.Many gate hinges have an adjustment. Quarter turns, checking after each.
Check whether the drag is seasonal.Timber swells in wet weather. If it only drags in winter, planing it will leave a gap in summer.
If planing is genuinely needed, take the gate off and remove very little at a time.It cannot be undone. Check the fit repeatedly.
Seal any planed edge and re-treat the whole gate with preservative.Bare timber absorbs water and swells straight back.

Tips

Fitting a gate wheel to the closing edge supports the weight and is a cheap fix for a heavy gate that has dropped slightly.
A diagonal brace running from the bottom hinge corner up to the opposite top corner is what stops a gate sagging. If yours runs the other way, it is doing nothing.
Treating a gate annually with preservative extends its life dramatically, particularly the end grain at the bottom.

Common mistakes

Adjusting the gate when the post has moved — The post is the cause. Fixing the gate to a moving post just delays the same problem.
Planing a gate that only drags in wet weather — It will be visibly gappy in summer once the timber dries and shrinks.
A brace fitted the wrong way round — The brace must run from the bottom of the hinge side upward. Reversed, it provides no support.

Questions people ask

Why has my gate dropped?

Usually the hinge post has rotted at ground level or its concrete has failed. Push the post — if it moves at the base, that is the cause rather than the gate or hinges.

Which way should a gate brace run?

From the bottom of the hinge side diagonally up to the top of the latch side. That puts the brace in compression and supports the weight. The other way round it does nothing.