What Is Mortar?

Mortar is a fundamental building material found in most modern and historical buildings. Its significance in construction dates back to ancient times, with evidence of its earliest use traced to around 10,000 years ago in Israel. Much of the ancient mortar still in existence remains durable today - a testament to the long-lasting nature of the material.

In practice, mortar is used to bind stones, bricks, or tiles together. More specifically, a mortar joint can act as a sealant, bearing pad, or the glue that sticks units together yet keeps them apart.

In this sense, mortar performs as a gap-filling adhesive. Screed is a type of mortar that has a finer grain appearance, which is often used to add a protective, smooth finish to concrete floors.

Mortar Screed Testing

Mortar & Screed Test Services

Today, mortar and screed testing is crucial to determine if the mix is suitable for the construction, replacement, and repair of materials in new and existing infrastructure. At CTS, we carry out a wide range of in situ mortar and screed test services in hospitals, schools, shops, and warehouses. We can also extract fresh samples for laboratory analysis.

A key screed test method we offer is In Situ Crushing Resistance (ISCR) testing, or floor screed testing. This can be completed in situ to determine the resistance of laid screeds to the crushing effect caused by imposed loads and traffic during use. It requires subjecting the screed to repeat impact blows by dropping a weight vertically onto a hardened steel anvil in contact with the screed surface.

We can also conduct hygrometer surveys to determine the humidity of screed mixes before they are used. This screed test is important before floor products are laid and bonded to the screed surface to ensure the materials will perform as expected. 

Laying a resin floor

Specifications for Mortar & Screed

To achieve adequate strength and durability, mortar in the UK is produced to specification BS EN 998-2 (Specification for mortar for masonry - Part 2: Masonry mortar). Mortar material testing is covered by BS EN 1015 and BS 4551.

Screed is no longer within the scope of the mortar standards and is now covered by BS EN 13318 (Screed material and floor screeds - Definitions) and BS EN 13813 (Screed material and floor screeds - Screed material - Properties and requirements).

Under BS EN 13318, screed is defined as a layer or layers of screed material laid in situ, directly onto a base, bonded or unbonded, or onto an intermediate layer or insulating layer, to obtain one or more of the following purposes:

  • To obtain a defined level
  • To carry the final flooring
  • To provide a wearing surface

Screed material testing is covered by BS EN 13892.

Collecting a few samples of mortar for testing

Our Mortar & Screed Test Types

Our in situ and laboratory mortar and screed test services include floor screed testing, compressive strength of screed testing, and compressive strength of mortar testing, as well as:

Test

Method What it shows
In-Situ Crushing Resistance of Screeds BS 8204-1 Resistance to the crushing effect of imposed loads and traffic
Hygrometer Survey BS 5325 Measurement of relative humidity values above porous surfaces such as screeds and concretes
Flexural and Compressive Strength of Screed BS EN 13892-2 Determines the flexural and compressive strength of prisms
Mix Proportions of Screed BS 4551 Determines traditional volume proportions and screed designation
Adhesive strength of hardened rendering and plastering mortar BS EN 1015-12 Determines the maximum tensile stress applied by a direct load at right angles to the surface of the rendering
Flexural and Compressive Strength of Mortar BS EN 1015-11 Determines the flexural and compressive strength of prisms
Mix Proportions of Mortar BS 4551 Determines traditional volume proportions and mortar designation
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