The joints go first.

How do I know if my mortar needs repointing?

Do the scrape test. Take a key, a screwdriver, or the corner of a putty knife and drag it firmly along a mortar joint.

Sound mortar barely marks. It feels like scratching stone. Failing mortar gives way — it powders, it comes out in crumbs, or the tool sinks in. If you can dig a joint out to the depth of your key without much effort, that wall needs repointing.

Do it in a few places: a weather-facing wall, a sheltered wall, near the ground, and up near the roofline. Joints rarely fail evenly, and knowing which areas have gone is how the job gets scoped honestly.

What does failing mortar look like?

Recessed joints where the mortar has washed back behind the face of the brick. Sandy grey dust collecting at the base of the wall or on window sills. Hairline cracks running along the joint lines. Gaps you can see daylight or a shadow line in. Mortar that has gone noticeably paler and softer than the same mortar in a sheltered corner.

Vegetation is a late sign. Moss or small plants growing out of a joint means the joint is holding water and has enough open volume to hold soil.

• Joints recessed behind the brick face
• Sandy dust at the base of the wall
• Cracks following joint lines rather than crossing brick
• Mortar you can remove with a key or a fingernail
• Moss, plants, or open gaps in the joints

Can I repoint brick myself?

On a small cosmetic area of a modern wall — a few joints on a garden wall, a patch by a step — a careful homeowner can do a respectable job. It is slow, fussy work, but it is not mysterious.

Where DIY goes wrong is the mix, and it goes wrong invisibly. A hard modern mortar on soft brick does not fail; the brick does. Faces pop off, edges crumble, and by the time it shows the damage cannot be undone.

The second common problem is depth. Smearing new mortar over the face of failed joints without cutting the old material out gives you a wall that looks repaired and holds water behind a thin skin. It falls off in sheets a few winters later.

If the house is old, if the area is large, if it is high up, or if you cannot confidently identify the existing mortar, that is the point to hand it over.

How often should brick be repointed?

Not on a schedule — on condition. A well-built wall with a matched mix, decent overhangs, and gutters that work can go decades without needing anything.

In practice, weather-facing elevations, chimneys, parapets, and anything near the ground go first, and those areas may need attention long before the rest of the house does. Repointing a whole building because one wall failed is usually unnecessary.

What's the difference between tuckpointing and repointing?

Strictly speaking they are two different things. Repointing is the repair: cutting out failed mortar and packing in fresh. Tuckpointing is a decorative technique where a joint is filled with mortar coloured to match the brick, then a fine ribbon of contrasting mortar is laid into it to imitate very thin, precise joints.

In everyday use, most people — and plenty of contractors — say tuckpointing when they mean repointing. If someone quotes you tuckpointing on a standard brick house, they almost certainly mean the repair.

It is worth asking, because the two jobs are not the same amount of work.

Why is my mortar falling out?

Water and time, mostly. Mortar is the sacrificial part of a wall by design — it is meant to erode so the brick does not. Rain, freeze-thaw cycling, and runoff from a bad gutter accelerate that.

Other causes: a previous repair done with the wrong mix that never bonded, joints that were never packed to depth, salt exposure near steps and driveways, and movement in the wall opening joints faster than weather ever would.

If mortar is falling out of one specific band or one corner, look above it for the water source before assuming the whole wall is due.

How much mortar loss is too much?

A useful rule of thumb: once joints are eroded back roughly a quarter inch behind the brick face, or once you can remove material by hand, the wall has stopped being weathertight and repointing is due.

It becomes urgent when brick starts moving, when whole units can be rocked, or when joint loss is deep enough that the wall's bearing is affected. At that stage you are past repointing on that section and into rebuilding.

What mortar should be used on an 1800s home?

A lime-based mix, softer and more absorbent than the brick around it, with sand chosen to match the original for colour and grain. Not a hard modern bagged mortar.

The match gets judged against clean original mortar in a sheltered spot rather than the weathered face, and it is worth doing a test area first because mortar changes colour as it cures.

Can modern mortar damage old bricks?

Yes, permanently. This is the most expensive mistake in masonry.

Hard, dense Portland-based mortar is stronger and less permeable than soft historic brick. It stops the wall breathing and it stops the wall moving. Moisture that used to leave through the joints is forced out through the brick faces instead, freezes there, and pops them off. Thermal movement that used to be absorbed by soft joints is taken by the brick edges instead, and they crumble.

You cannot put a face back on an original brick. That is why the mix matters more than almost anything else about a repointing job.

How long does repointing last?

Matched properly, cut to depth, packed in layers, and tooled and cured correctly, repointing is measured in decades — often long enough that it is the next owner's problem, not yours.

Done badly, it can fail in a handful of winters, and if the mix was too hard it takes brick with it on the way out. The difference is not the material cost. It is the diagnosis and the workmanship.