Specialist traditional lime putty repointing - Oxfordshire (Fully certified).
Lime putty was used historically to make mortar but for it to be successful it has to be well matured. Most suppliers sell it aged 4 - 6 months but that's far too young. A strong mortar comes from putty laid down for at least 12 months. The reason for this is that the maturing process reduces the grain size of the slaked quicklime which means the mortar becomes more weather resistant and more resilient to the outside environment. Mortars made from putty matured for short times should only ever be used internally for pointing and plastering.
Below: The Old Bakery at Shrivenham before refurbishment work began.
After: 1 x lime putty, 2x Ginger Wilkes and 1 x 50/50
Before: Buckland cottage.
After: a coarse grain lime mortar with the addition of fine washed sand.
If you'd like to see how this work was done then please view it on YouTube:
Lime putty (commonly referred to as non-hydraulic lime or fat lime) is a product used exclusively on older properties. Putty mortar was originally used in period property construction and its origin can be traced back as far as Roman and Egyptian times.
It is slightly softer and more vapour permeable than Natural Hydraulic lime (NHL) because of its high free lime content. It makes a lighter colour mortar which won't cure unless exposed to air. Although ideal for restoring historic buildings - it can sometimes difficult to use during wet winter months and should preferably be used when temperatures are 10 degrees or above. It also requires a different skill level than natural hydraulic lime and can sometimes be more time consuming to employ.
Before (Pury End, Northamptonshire).
When you know the right tools, procedures and mortars there's no telling what can be achieved.
For further information on this, please go to:
Please see the photos below for examples of what this looks like when mixed with a good sand.
Close up view:
The best putty to use is one which has been matured for years.
Hockmore Cottage, Cowley, before:
When to use putty:
- Non-hydraulic lime is compatible with weak and weathered stone
- If your building is old and is prone to movement because it sits on insubstantial foundations then lime putty is ideal because it is argued to be the most flexible mortar and many believe it copes better with settlement
- When it is important that mortar and not the stonework becomes the sacrificial element in the building.
When not to use lime putty:
When the building is very damp. Putty requires a dry environment to cure. Damp buildings prevent this therefore NHL should be used as this will set in the presence of moisture. If NHL is not to be specified then putty with sufficient pozzolan will suffice. This will enable it to cope with:
Very exposed areas and chimneys.
The winter months.
When curing times are a priority.
Before: earth-lime built barn in Hampton Poyle.
During: rake out and new mortar application.
After final brushing. Now carbonation starts.
If you'd like to know more then please go to http://mike-teacherlife.blogspot.co.uk/2016/05/the-use-of-lime-putty.html
For repointing in Lechlade, Eastleach, Holywell, Westwell, Signet, Shilton, Windrush, Fulbrook, Aston, Faringdon, Fairford, Kempsford, Buscot, Pusey, Yelford, Brighthamsted, Eynsham, Bampton, Swindon, Stanford in the Vale, Wantage, Buckland, Lambourn, Oxford, Wootton, Woodstock, Witney, Burford, Finstock, Kidlington, Blenheim, Coombe, Stonesfield, Bladon, Hailey, Long Hanborough, Hampton Poyle, Abingdon, Tackley, Minster Lovell, Fyfield, Southrop, Inglesham, Highworth, Fernham, Watchfield, Shrivenham, Uffington, Coxwell, Stow-on-the-Wold, Moreton-in-the-Marsh etc.