Frequently Asked Questions

Can concrete and mortar be colour matched?

We do not guarantee a colour for our packed products. Concrete and mortar can be coloured by adding pigments. Mortar can also be tinted by specialist companies to match existing brickwork. You may find this website useful: https://www.diydoctor.org.uk/projects/Matchmortar.htm 

Which area does one bag of Sand Cement Mortar cover?

One MaxiPack of Sand Cement Mortar typically covers 22 standard bricks or 15 standard blocks. This are estimates and depend on the design of your brick.

What does ‘workability’ mean for mortar products?

Added workability is where admixtures or additional water are added to improve the flow of the mortar. Although addition of water can increase the flow, the water-to-cement ratio is thus reducing the strength of the end product. Trials should be carried out to assess the workability and suitability of admixtures.

What is the aggregate size in 40N Concrete?

4/10mm Limestone is used as the coarse aggregate in our concrete mix.

What is the minimum cement content in 40N concrete?

Approximately 380 kg/m3

How much concrete does one bag of 40N or Multipurpose Concrete produce?

One bag of 40N or General Multipurpose Concrete produces 0.01m3 of fresh concrete.

What coverage can I achieve with a bag of 40N or Multipurpose Concrete?

When mixed with approximately 2 litres of water, a MaxiPack20 pack will produce approx. 0.008m3 of concrete and cover:
0.10m2 @ 75mm thick
0.08m2 @ 100mm thick

Is 40N Concrete sulphate resistant?

40N Concrete is a dry mix bagged concrete. If the added water content recommended on the packaging is not exceeded the product should fulfil the requirements of a Design Chemical class DC-2.

Other materials would not be considered to be sulphate resistant other than our Low Carbon Sulphate Resistant Cement specifically aimed at conditions where sulphate resistance is required.

Is there a CE mark for 40N Concrete?

There is currently no harmonised EU standard for dry cementitious mixes, therefore the product is not CE-marked. 40N Concrete is produced in accordance with BS 5838, test results and certification for the constituent materials used within 40N Concrete are available on request.

What does ‘workability’ mean for concrete products?

Added workability is where admixtures or additional water are added to improve the flow of the mortar or concrete. Although addition of water can increase the flow, the water-to-cement ratio is thus reducing the strength of the end product. Trials should be carried out to assess the workability and suitability of admixtures.

What temperatures can concrete be used in?

Please refer to the relevant Technical Data Sheet on our webpages. As a guide, cement-based materials should not be used below 5oC or above 30oC

How should Drive Repair Asphalt be used?

Drive Repair Asphalt is a temporary pothole repair material for domestic driveways and not suitable for roads. Please refer to the reverse of the packaging or the technical data sheet on our website for instructions of use

How much of decorative aggregates is needed for a specific area?

Please refer to the table below to establish how many bags are required to cover a certain area.

This are only estimates, they vary depending on the product and nature of your ground preparation.

What does ‘added workability’ on Multicem mean?

It relates to the additional limestone content of the product which makes it more workable.

Does sand need to be added to HS52?

Yes, coarse and fine aggregates should be added in suitable quantities to produce the concrete or mortar mix required for the application.

Can admixtures be added to Multicem and other cements?Multicem already helps produce a smoother, more cohesive mix reducing the water required for a given workability, leading to lower risk of segregation and bleeding and resulting in a concrete which is more durable and has enhanced resistance to frost. Further addition of air-entraining plasticising admixturesshould not be necessary, but if needed should only conducted after trial mixes.

Admixtures such as air-entraining agents and workability aids are compatible with High Strength 52,5 cement. It is recommended, however, that trial mixes are carried out to determine optimum properties.

What temperatures can the cement products be used in?

Please refer to the relevant Technical Data Sheet on our webpages. As a guide, cement-based materials should not be used below 50^oC or above 30^oC.

What is the shelf life of white cement?

The shelf life of cement is related to the Hexavalent Chromium content Cr(VI).
In white cement the Cr(VI) content is naturally low and does not require a shelf life to be stated on the packaging.
All cements should be stored in dry conditions to avoid hydration. White cement should be used within 12 months of the packing date which is printed on the bag.

Where can Low Carbon Cement be used?

Our low carbon cement is suitable for most applications

Why is it called Low Carbon Cement?

Compared with traditional CEM I the embodied CO2 content of this product is significantly lower, refer to our Technical Data Sheet for further information. (Robert: can you add the link to the webpage?)

Can Low Carbon Cement be used for applications where sulphate resistance is required?

Yes, it is a CEM III/A+SR type cement. Therefore it can be used where sulphate resistance is required.

Will Low Carbon Cement develop the same strength as General Purpose and MultiCem?

Early age strengths are marginally lower than General Purpose and MultiCem but 28-day strengths are comparable.

What is the strength development of Postfix? How long does it take? What strength do I get?

The minimum strength levels achieved after one and four hours and 28 days are given in the table below:

Does cement need to be added to hydrated lime?

Yes. In fact, hydrated lime is added to cement-sand mortar to promote workability in the fresh mortar, and to promote ‘self-healing’ in the hardened mortar. Hydrated lime on its own will not set and harden in a way that is useable in bricklaying.

Which mixes proportions should be used with Hydrated and Natural Hydraulic lime?

The mix proportions depend on the application for the mortar. Please refer to our technical datasheets for these products for guidance. 

Why has the render cracked?

Render can crack due to a number of reasons, these include environmental conditions such as temperature, humidity, wind, direction of sunlight.

Correct curing practices are important should be undertaken in order to maintain humidity. Poor curing will cause the loss of moisture within the mix. As a result, not all the cement will have hydrated causing weak bonds and therefore potential cracking.

The type of substrate can also affect cracking in render if correct measures are not used to prevent loss of moisture from the render. An assessment of the type of brick or block should therefore be undertaken first.

Pronounced cracking may be due to drying shrinkage. Small areas can be renovated by the use of fillers.

In case of pronounced cracking in render and substrate seek the advice of a structural engineer or designer. Further advice can be sought from the Mineral Products Association: https://www.mortar.org.uk/documents/miadata14.pdf

Is the MSDS on the website the latest version?

Yes, the latest, current version is always maintained on our website.