Man in protective gear laying Porotherm clay block walling

How does Porotherm compare against traditional materials?

Our Porotherm clay block walling system is an innovative method of construction with the reassuringly traditional values of clay material.

As a complete building solution, the Porotherm system offers properties and efficiencies that can be favourably compared to virtually every building fabric on the market. In this article, we compare the benefits of Porotherm to other materials such as Concrete Masonry, Light Steel Frame, Timber Frame and Aircrete Thin Joint Masonry.

Porotherm vs traditional blocks video

Watch our comparison video of using Porotherm versus traditional blocks for building a house. 

Porotherm compared to Concrete Masonry

Typical laying speed
Programme benefits
Movement Joints

25 -30m² per man, per day

1mm beds, no mortar in vertical joints, blocks interlock mechanically. Storey height capability without the need to back up allows the external envelope to be removed from the critical path.

Reduced time to achieve a water-tight shell means quicker availability for finishing trades

Once applied to the blocks, the bed joint mortar begins to set within 30 minutes. Significant strength is gained after a matter of hours with full strength reached at circa 24 hours.

Supplied with block free of charge. Circa 95% less water built in

With the new PLS 500 100mm block weighing 10.6kg.


Porotherm blocks are typically lighter in weight than concrete blocks, with the new PLS 500 100mm block weighing 10.6kg.

Porotherm blocks have rounded ends and no sharp arrises. Using the roller to apply the bed joint mortar reduces the risk of skin contact thus reducing dermal burns etc.

The walling system is stable and rigid with storey height achievable in a working day

Core Range compressive strengths are typically ≥ 10 N/mm2 hence there is a reduced requirement to keep multiple block types on-site. This helps minimise the risk of the wrong block being used in the wrong location.

Reduces storage requirements on tight sites

Typically 20m centres

There is a minimum waste on mortar and typically a 2% block wastage

The blockwork typically has enhanced Psi values

Concrete Masonry

12 - 15m² per day

10mm vertical and perpendicular bed joints. Height capability is restricted by the need to back up with facing brick and insulation after 1.2m

A material cost to the project.

Once the wet bed joints are laid the mortar is slow to set with full strength reached at circa 48hrs

Dense concrete blocks are not designed for single hand handling, weighing up to 19kg.

The application of mortar introduces the risk of dermal burns etc.

Dense concrete walls with wet mortar beds are not stable when unsupported

Dense blocks are manufactured to a range of compressive strength

Typically 3 and 6m centres

Typical industry guidelines suggest 40% waste against mortar and 15% waste against block

Dense concrete blocks provide less thermal resistance

Porotherm compared to Light Steel Frame

Internal partitions
Thermal performance
Internal fit out

Cavity or monolithic walls designed to be clad with a wide range of impervious finishes

Porotherm walls are suitably robust for use on all development types

Portherm's thermal conductivity and specific heat capacity contribute to its excellent thermal mass.

The external walling envelope is removed from the programme’s critical path in providing a weatherproof structure

Internal walls can be constructed at the same time as external inner leaf walls.

Light Steel Frame

Designed to be clad – typically with plasterboard to the internal face, insulated between studs, clear cavity and external skin of masonry or rain-screen

Lighter sections for internal partitions may not be suitably robust for all application

The light steel frame structure provides no contribution

Dependent upon cladding

Internal fit out cannot commence until external cladding has been installed

Porotherm compared to Timber Frame

Thermal mass
Upper floor depths
Post completion shrinkage
Flexibility of design

The price per square metre of block-work is comparable to other masonry materials. However, the speed and efficiency that the Porotherm system offers on-site creates substantial savings in virtually every area, such as reduced labour and mortar costs

Class A1 rated, no extra security measures or additional insurance required

With more thermal mass, Porotherm regulates temperature variations through thermal capacity effects to protect against cold in winter and ensure a comfortable and healthy room in summer

Standard floor zones can be used with the Porotherm walling system, typically 360mm, thus decreasing the number of brick courses per floor by two, reducing ridge height

No settlement occurs therefore no extra movement joints are required

No shrinkage problems occur

Short lead times. Change incorporated with ease during site construction

Timber Frame

Modern Masonry Alliance typically advise Timber Frame 15% more expensive than equivalent masonry construction

Specific security measures required with additional insurance

With low thermal mass due to 75% of walls built-up with insulation, timber frame has a reduced capacity to regulate temperature variations

Floor zones are generally 500mm in depth

Compression joints are required at all window cill areas and at storey level

Potential for shrinkage cracks due to timbers drying out

Lengthy lead in time for panel design and manufacture. Changes are difficult to accommodate

An infograph showcasing the use of Porotherm compared to Timber Frame.

Porotherm compared to Aircrete Thin Joint

Movement Joints
Additional movement control
Product accuracy

10 N/mm²

Typically 20m centres

Free with blocks (beds only). Less water built-in

Note required

During the manufacturing process Porotherm blocks are ground top and bottom with a tolerance of +/- 0.5mm and therefore are virtually flat

Aircrete Thin Joint

2.9 – 8.7 N/mm²

Typically 6m centres (3m from corners)

Greater volume (beds and perpendicular) at additional cost

Bed joint reinforcement is frequently every second course and 2 courses below and 2 courses above window/door openings

To avoid unnecessary rasping TLMA or TLMB dimensional tolerance class blocks must be used

An infograph showcasing the use of Porotherm compared to Aircrete Thin Joint.

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