Ash GP Concrete Datasheet
Side view of a Ash GP Block.

Ash GP Concrete Block

Ash GP medium density concrete blocks are robust and durable, making them the perfect choice for walls built above and below ground. Manufactured to BS EN 771-3, their textured faces provide an excellent surface for mortars, renders and plasters. They also provide a strong base for holding fixings.

Ash GP blocks contain a proportion of recycled materials, and their sustainability performance has been verified through an Environmental Performance Declaration (EPD).


Specification & Application

Thermal Properties



Block Wall Ties

Under normal conditions, wall ties should be embedded 50mm into the mortar on each leaf, staggered in alternate courses and spaced in accordance with the following.

Table 5 – Wall Tie Spacings

Leaf Thickness
Cavity Width
Horizontal Spacing
Vertical Spacing
Ties per m²
Less than 90mm50 - 754504504.9
Over 90mm50 - 1509004502.5

Block Mortar

Generally, the mortar type for work above ground level should be designation (iii) / Compressive Class M4. Designation (ii) / Compressive Class M6 is needed for work below ground in conditions where there is a risk of saturation with freezing.

Table 6 – Mortar Mixes

Mortar Designation
(as per BS 5628-3)
Compressive Strength Class
(as per BS EN 1996)
Recommended mix proportions of materials by volume
(iii)M41:1:5 to 6 - Cement:Lime:Sand.

1:5 to 6 - Cement:Sand with or without air entrainment.

1:4 to 5 - Masonry Cement:Sand (with non-lime filler).

1:3½:4 - Masonry Cement:Sand (with lime filler).
(ii)M61:½:4-4½ - Cement:Lime: Sand.

1:3 to 4 - Cement:Sand with or without air entrainment.

1:2½:3½ - Masonry Cement:Sand (with non-lime filler).

1:3 - Masonry Cement:Sand (with lime filler).

Site Practice

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The Whiteley: Bespoke Blockwork For A Unique Restoration

Mixed Use

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Construction photo of The Whiteley.