Lime VS Portland Cement? Which Is Better?

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lime vs portland

There are only two kinds of cement used in masonry, Lime and Portland.

Cement is like flour, the essential ingredient in baking that can be used to make bread, muffins, etc. Similarly, cement is the essential ingredient for brick mortar, concrete and paving stones. Many people confuse cement and concrete, but they are not the same: Cement is like the flour and concrete is like the bread. Cement is basically the glue of masonry.

So this brings us back to our original question: Which is better, lime cement or Portland? Each has its pros and cons.

Portland Pros

Portland Cons

Lime Pros

Lime Cons

High StrengthNo FlexibilityFlexibility Slow set time
Quick Set Time Impermeable to waterAutogenous healing Low strength
Sets UnderwaterBad for EnvironmentPermeability 
Less ExpensiveHigh StrengthWorkability 
  Better for Environment 

Mortar Types

Since each cement has different good and bad qualities, most common mortars combine both types of cement.  There are 5 main types of mortar, suitable in different applications, each with different strengths, properties and applications.

Type M – 3200 PSI – 100% Portland

Type S – 2200 PSI – 67% Portland – 33% lime

Type N – 1400 PSI – 50% Portland – 50% lime

Type O – 1000 PSI – 33% Portland – 67% lime

Type K – 750 PSI – 100% lime

Bricks and wall stones are usually laid in Type N. This 50-50 mix combines the good qualities of the Portland (strength and fast set time) with the flexibility, permeability and workability of lime.

Type M (pure Portland) or Type S must be used for anything exposed horizontally to the elements, such as a stone patio, door threshold or wall coping. This is because water pooling and salt will quickly erode the surface (usually within one year) if the mortar is Type N or lower.

Types O and K are rarely used (Type O is usually for glass block and Type K is practice mortar).

Types of Lime

The element that gives the cement strength is the clay content. Portland cement is about 30% clay-based, while lime is usually about 5% clay. However, there are three basic strengths of lime mortar, depending on the amount of clay present. The closer the clay percentage gets to 30%, the closer it is to a Portland cement, since the strength will be the same.

So Which Type of Cement Is Better?

There is no right or wrong type of cement, but there are many right and wrong applications of each. This leads to confusion as to what ratio is right for each circumstance. Many people know that using pure Portland on natural stone is bad (and it is), but in our Canadian climate you have to lay a flagstone patio in pure Portland if you want it to last more than a couple of years. Lime and Portland cements are equally useful to the trade, and only knowledge and experience will tell you what the right cement or ratio is.


  1. Iuval on 31 March 2014 at 1:54 pm

    Is the lime that is mixed with Portland cement in types S, N and O mortar. hydraulic or non-hydraulic?

  2. sadhu aadidas on 27 June 2014 at 5:06 am

    Hello there. I suppose one feature has been left out in comparing the pros and cons of the two cements – the life of the mortar in which lime fares far better than portland. Again the strength of the mortar is perhaps evaluated only for short term, if compared for a period of say, a 100 years, perhaps lime again would fare better.

  3. Prem Pratick Kumar on 4 May 2015 at 1:14 pm

    Very well written article.

    Prem Pratick Kumar

  4. JP on 15 August 2015 at 11:28 am

    So what do you use on stone foundation walls, on the exterior, for repointing above-grade, rubble stone foundation walls? My understanding is that the Portland is bad, so which of those grades do you use instead?

  5. craig on 27 October 2015 at 8:46 pm

    Well written article, perhaps if more Mason were familiar with these principles we would have less project failures. Air floated clay can also be used to make mortar mixes instead of lime. Also like to point out that mixes should be tailored to the strength of the material you are laying(ie laying reclaims with high lime content). That way if there is movement in a structure it will crack the mortar joints and not the material itself making repair a lot easier.

  6. Larry Smith on 4 January 2016 at 2:12 pm

    Please in your next post discuss the significance of the lime mortars, historically, and please define their ability to breathe.

  7. damien on 21 January 2016 at 4:35 am

    I have damp issues on internal walls ,ive re-rendered with sand ,cement and waterproof add mix 5 yrs ago ,we also had the cavity filled with insulation ..
    i think the walls are sweating ,if i had rendered with lime would this have happened I’m going to extract the cavity.
    the walls were originally lime mix and cavity free…

  8. Dana Tapley on 19 March 2016 at 9:53 pm

    Hi, I would like to know what ratio to mix lime with what. I don’t want to use portland cement. Do I have to add clay to the mix?

  9. Andy on 15 May 2016 at 4:45 pm

    Typically Portland cement is mixed with hydrated lime, sand, and water to make mortar. Lime putty mortars are not very common for new construction but are more often used on historic building constructed with lime putty mortars. Additionally there are two other types of cement that are often used for preparing mortar. They are masonry cement and mortar cement. Refer to ASTM C270 for more information. Masonry cement and mortar cement are proprietary products that contain either Portland cement or blended cements that are mixed with a plasticiser such as hydrated lime of ground limestone along with other materials to enhance he mortar properties such as workability or air entrainment. Masonry cement mortars are the predominant mortar type for the southeast United States.

  10. Dan on 15 May 2016 at 6:19 pm

    Thanks for the info.

  11. Emily on 19 May 2016 at 11:34 pm

    Toduochwn! That’s a really cool way of putting it!

  12. Percy Jack on 8 July 2016 at 8:05 am

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  13. john on 26 December 2016 at 2:56 pm

    My take is this:

    Lime is beautiful, had been used for facades, blocks, in building in the past. Mold free (but not water tight!)

    Today lime is in portland cement, brick mortar, maybe drywall and compounds, plasters, pool liners, more: but carefully and mixed with other things.

    However it’s not suggested for (outdoor/wet) floors or in bathroom / steam rooms or with (ceramic) tile for many technical reasons (issues that arise a customer would complain about, or long-term commercial liability if it fails long-term).

    For DiY for niche use (anywhere not critical) lime is a great project. For professional use, let the manufacturers do the mixing and use only the approved mixes for applications 🙂