Cellar wall repointing

As its a solid wall in a 1920's cellar it would probably need tanking to stop the damp,(usually from the outside) Rake out old mortar and re-point using damp a proof additive to the mix may slow it down

Give the wall a good clean down then flush point the wall then give it a good coat of tanking slurry but if the floor is wet then a membrane and float pump will be needed without inspection first Good luck

Rake out the joints it is probably lime mortar so re use a lime mortar mix 3 and1 ratio, we had a property in Cornwall forever damp and weeping, to combat that problem we used a mix of cement and SBR brushed on in 3 coats , plastered over the top no problems after.

Efflorescence is a sign that moisture is passing through the wall, so simply repointing may not solve the underlying problem. However, if the mortar is crumbling, repointing the affected areas can help protect the brickwork and prevent further deterioration. On a property of that age, it’s important to use a suitable breathable mortar, such as a lime-based mortar where appropriate, rather than trapping moisture in the wall. It would also be worth identifying the source of the damp so the root cause can be addressed when your budget allows.

Finding the source of the damp is key. Regardless how well you repoint and protect, the issue will resurface if not dealt with. Older buildings often have to have cellars built to allow water through and pump out systems.

Remove the loose/crumbling mortar and salts carefully. Repoint with a breathable mortar appropriate to the original masonry, often a lime-based mortar in older construction. Avoid hard cement-rich mortar, as it can trap moisture and damage softer brickwork. Repointing won’t stop the damp or efflorescence; it mainly restores the joints and helps maintain the wall while you plan a proper moisture-management solution. Improve ventilation and address any obvious external sources of water where possible.Many thanks

Rake it out 20mm and repoint it in lime nhl2 mortar

Yes, if the mortar is badly crumbling or joints are becoming deeply eroded, localised repointing can help protect the masonry even if you can’t tackle the wider damp problem yet. For a 1920s cellar, it’s important to use a compatible, breathable mortar—often lime-based—rather than a hard cement mix, which can trap moisture and worsen salt damage. Repointing won’t cure the damp itself, so the moisture source should still be investigated when possible. If the brickwork is loose, bulging or significantly deteriorated, get a surveyor to inspect it first.