LIME MORTAR HAS CRACKED

Probable Causes

Remedial Action

1. Base was not pre-wetted
2. Mixture was too wet
3. Day was too hot
4. Wind was too strong
5. Sand was not clean
6. Work was not compressed
7. Too much lime to sand in wide joints
   (or any combination of these)

• Compress mortar if not too hard
• If hard, try gentle wetting with compression
• If too hard, make fine mortar by sieving coarse mortar, pre-wet and fill cracks pressing well home with small wooden spatula.

LIME HAS LEACHED OUT OF MORTAR

Probable Causes

Remedial Action

1. Work was not protected from rain until carbonation occurred.

• Remove and replace with a fresh mix.
• Stain not easily removed but may be dissolved with carbonated water.
• Seek experienced advice.

LIME MORTAR WILL NOT HARDEN

Probable Causes

Remedial Action

1. Weather is cold and wet
2. Mortar was too wet
3. Work is unventilated

• Improve ventilation and draught N.B. Never use de-humidifiers - this will cause failure
• Patience

LIME MORTAR HAS SMEARED BRICK/STONE

Probable Causes

Remedial Action

1. Careless work
2. Unsuitable tools
3. Intentional 'buttering'

• If brick/stone was pre-wetted, just allow to dry and brush off
• If not pre-wetted, seek experienced advice
• Stain may be dissolved with carbonated water
• If intentional, to match original, which is commendable: no action

LIME MORTAR HAS HARDENED BUT IS CRUMBLY/POWDERY

Probable Causes

Remedial Action

1. Failure to carbonate (absorb air)
   a) Backing not pre-wetted.
   b) Surface over-worked (dense face).
   c) Work is in confined space.

• Try wetting again with lime water.
• Seek experienced advice.

LIME PLASTER HAS CRACKED IN FIRST COATS

Probable Causes

Remedial Action

1. Base was not pre-wetted.
2. Shrinkage in lime putty.
3. Shrinkage due to dirty sand.
4. Too little animal hair.
5. Coats were too thick.
6. Mixture was too wet.

• No action required (makes a better key).
• If really weak, remove and knock up, then re-apply: add no water - just hard work.
• Seek experienced advice.

LIME MORTAR HAS CRACKED IN FINAL COAT

Probable Causes

Remedial Action

1. Base was not pre-wetted.
2. Previous coats had not hardened.
3. Application is more than 3mm thick.
4. Surface has not been well worked.
5. Mixture was too wet.*

• Wet with lime water and give a good re-working with wood float.
• Fill fine cracks with more stuff after pre-wetting.
• * Allow for some evaporation before re-working.

LIME WASH HAS CRAZED

Probable Causes

Remedial Action

1. Insufficient pre-wetting.
2. Wall was hot (extremely dry).
3. Limewash coat was too thick.
4. Coats had not hardened between applications.

• Thoroughly soak and work over with brush to compress and fill.
• Thoroughly pre-wet and apply thinned coats to fill cracks.

LIME WASH POWDERS OFF

Probable Causes

Remedial Action

1. Applied without pre-wetting.
2. Area of wall was hot and dry.
3. Too much pigment added.

• Try applications of lime water.
• Remove and re-apply.
• Seek experienced advice.