Class H – Erections and extensions of industrial buildings and warehouses

Class H allows for the erection of a new industrial building, or the extension of an existing one or indeed the alteration of an existing building. This also applies to warehouses that fall under Use Class B8.

One important factor is that any development is within the curtilage of an existing industrial building or warehouse and must be used for an industrial or warehouse purpose.  You are limited to a maximum of 100 sq m on Article 2(3) land or 200 sq m otherwise. The expansion of an industrial building is limited to 10% or 500 sq m whichever is the lesser.

As far as height of the new industrial building in concerned this is limited to 5 metres if within 10 metres of the boundary or 15 metres otherwise and nothing can be within 5 metres of the boundary.

At no time can the new building cause a reduction in parking or turning of vehicles and forget a new industrial building within the curtilage of a listed building for obvious reasons.

You can check the legislation below for industrial buildings or warehouses. If you need any assistance, please contact us. 

Legislation

Class H – extensions etc of industrial and warehouse

Permitted development

H. The erection, extension or alteration of an industrial building or a warehouse.

Development not permitted

H.1 Development is not permitted by Class H if—

(a) the gross floor space of any new building erected would exceed—
(i) for a building on article 2(3) land or on a site of special scientific interest, 100 square metres;
(ii) in any other case, would exceed 200 square metres;

(b) the gross floor space of the original building would be exceeded by more than—
(i) in respect of an original building or a development on article 2(3) land, 10% or 500 square metres (whichever is lesser);
(ii) in respect of an original building or a development on a site of special scientific interest, 25% or 1,000 square metres (whichever is the lesser);
(iii) in any other case, 50% or 1,000 square metres (whichever is the lesser);

(c) the height of any part of the new building erected would exceed—
(i) if within 10 metres of a boundary of the curtilage of the premises, 5 metres;
(ii) in all other cases, the height of the highest building within the curtilage of the premises or 15 metres, whichever is lower;

(d) the height of the building as extended or altered would exceed—
(i) if within 10 metres of a boundary of the curtilage of the premises, 5 metres;
(ii) in all other cases, the height of the building being extended or altered;

(e) any part of the development would be within 5 metres of any boundary of the curtilage of the premises;

(f) the development would lead to a reduction in the space available for the parking or turning of vehicles; or

(g) the development would be within the curtilage of a listed building.

Conditions

H.2 Development is permitted by Class H subject to the following conditions—

(a) the development is within the curtilage of an existing industrial building or warehouse;

(b) any building as erected, extended or altered is only to be used—
(i) in the case of an industrial building, for the carrying out of an industrial process for the purposes of the undertaking, for research and development of products or processes, or the provision of employee facilities ancillary to the undertaking;
(ii) in the case of a warehouse, for storage or distribution for the purposes of the undertaking or the provision of employee facilities ancillary to the undertaking;

(c) no building as erected, extended or altered is used to provide employee facilities—
(i) between 7.00pm and 6.30am, for employees other than those present at the premises of the undertaking for the purpose of their employment; or
(ii) at all, if a quantity of a dangerous substance is present at the premises of the undertaking in a quantity equal to or exceeding the quantity listed in the entry for that substance in Parts 2 or 3 of Schedule 1 to the Control of Major Accident Hazards Regulations 1999;

(d) any new building erected is, in the case of article 2(3) land, constructed using materials which have a similar external appearance to those used for the existing industrial building or warehouse; and

(e) any extension or alteration is, in the case of article 2(3) land, constructed using materials which have a similar external appearance to those used for the building being extended or altered.

Interpretation of Class H

H.3 For the purposes of Class H, where 2 or more original buildings are within the same curtilage and are used for the same undertaking, they are to be treated as a single original building in making any measurement.

H.4 For the purposes of Class H—

“dangerous substance” has the meaning given in regulation 2 of the Control of Major Accident Hazards Regulations 1999;

“employee facilities” means social, care or recreational facilities provided for employees of the undertaking, including crèche facilities provided for the children of such employees; and

“original building” does not include any building erected at any time under Class H.

Industrial and Warehouse Extensions Page Updated:  8th August 2023