Noncommercial Mortar Products

Another choice to buying a readymade commercial historic lime mortars, is to mix a hybrid type of mortar. The following are a collection of mortar recipes and the ingredients needed to mix them. Most have a proportion of White Portland cement as a base factor. White Portland cement is a very hard cement, and too hard by itself for safe do no harm preservation work. This is why it is in smaller proportions to the other ingredients. Please never increase the Portland cement ratios in the recipes.

Here are two recipes from Oregon developed for historic preservation.

 

1 part White Portland Cement (recommended: ASTM C-150. Type 1)

4 parts Hydrated Lime (recommended ASTM C-207, Type S)

8 parts clean sand

White Portland Cement with extra lime mix to soften cement can be used to set stone in recessed base.

There is a commercial product available special ordered from Home Depot, that with added lime, closely matches Oregon’s’ recommendation. We have received permission to use this.

 

Quikrete White Glass Block Mortar Mix with 5 parts added hydrated lime.

Mix ratio… add slightly less than1 cup of hydrated lime to two cups of the Quikrete mortar mix. By adding the extra lime, the mixture is sufficiently weakened

 

This type “S” mortar mixture consists of (12 parts)

2 parts White Portland Cement

1 part lime

9 parts sand

Below grade repair work is always tricky at best and should be avoided when possible, because lime mortars don’t always behave well when below grade. The following is a recipe from New England that takes in to account the dampness of the soil and the areas soil pH.

 

1 part Portland

4 parts sand

Below are the different ingredients needed for the recipes above. You will also find more information on them under TECHNICAL...MSDS and Product Instruction Sheets. You may also find these items discussed under PRO VS CON...Methods or Bonding Agents. 

NHL 3.5 and 5 are here, because they are one of the best and easiest lime mortar mixes to put together. And because they are lime mortar products that require the addition of sand to make ready to use as a mortar. You will find a readymade lime mortar mix called Ecological Mortar (F) that does not require sand to be added under, PRODUCTS USED...Commercial Mortars.

St. Astier NHL 3.5

Manufacturer – St. Astier

Product Type – NHL 3.5

Availability – Now available through the CCUS, click the blue button below

NHL 3.5 quart...$5.00

NHL gallon...$15.00

NHL 55 lb. bag...$46.50

Click Here

NHL 3.5 - Moderately Hydraulic lime is used for laying or repointing brick, stone and terra cotta units even in extreme freeze-thaw climate cycles. It can be used to make scratch, brown and finish coats of exterior stucco or interior plaster. NHL 3.5 must have 15-25% “free lime” content and no more than 30% which is responsible for self-healing mortars. The available free lime goes into solution during subsequent rains and then re-crystallizes across open fissures, similar to the process that occurs in historic pure lime mortars. NHL maintains a hexagonal plate crystal structure which allows the plates to go in between each other for greater elasticity. In contrast, Ordinary Portland Cement (OPC) has a needle-like crystal structure which is brittle; buildings using OPC must incorporate numerous control joints to accommodate movement. Once properly installed and cured NHL 3.5 will reach over 750 p.s.i. in six months when blended with 2-1/2 parts clean, sharp and well-graded sand.

St. Astier NHL 5

Manufacturer – St. Astier

Product Type – NHL 5

Availability – Now available through the CCUS, click the blue button below

NHL 3.5 quart...$5.00

NHL gallon...$15.00

NHL 66 lb. bag...$46.50

Click Here

NHL 5 - Eminently Hydraulic lime is used for applications such as building or repairing wall head copings, pointing and parging the water table or foundation of a building and making lime concrete. Sea-bearing walls can be built or repaired with NHL 5 since it is immune to sulphate attack. Sulphate attack normally occurs in mortar prepared with OPC or when white cement has been introduced into synthetically created hydraulic lime to ensure a hydraulic set. The high percentage of tri-calcium aluminates found in OPC negatively reacts with the sulphates. This reaction produces an overall expansion and eventual disintegration of the mortar or concrete, especially in marine environments.

Manufacturer – Federal, Lehigh, and many others

Product Type – White Portland Cement C-150 Type 1

Availability – local const. supply stores, hardware’s, concrete companies

Manufacturer – Western, Chemstar, and many others

Product Type – Hydrated Lime C-207 Type S

Availability – local const. supply stores, hardware’s, concrete companies

Locate the finest and cleanest sand available. Remember: the color of the sand will tint the mortar you are mixing. Here are two choices of sands. Quikrete fine is most preferred, but the Premium Play Sand is of a finer grade and will work if nothing else is available. Glass Block sand is another several conservators like as well.

Manufacturer – Quikrete

Product Type – Commercial grade fine

Availability – local const. supply stores, hardware’s, concrete companies

Manufacturer – Quikrete

Product Type – Premium Play Sand

Availability – local const. supply stores, hardware’s, concrete companies

Manufacturer – Quikrete

Product Type – Glass Block Mortar Mix

Availability – local const. supply stores, hardware’s, concrete companies