[NOTE: For other updates to the "Technical Guidance" document, please view the following posts:
- This post for the January 2013 updates.
- This post and this post for the October 2013 updates.
- This post for the April 2014 updates.
- This post for the April 2016 updates.
- This post for the April 2017 updates.
- This post for the September 2019 updates.]

Introduction:

The Ministry of Housing, Communities and Local Government (MHCLG) has updated its "Permitted development rights for householders - Technical Guidance" document (note: this document provides advice relating to Part 1 of the GPDO). As such, the current and previous versions of the "Technical Guidance" document are now as follows:

• September 2019: Permitted development rights for householders - Technical Guidance (pdf) (link).
• April 2017: Permitted development rights for householders - Technical Guidance (pdf).
• April 2016: Permitted development rights for householders - Technical Guidance (pdf).
• April 2014: Permitted Development for Householders - Technical Guidance (pdf).
• October 2013: Permitted Development for Householders - Technical Guidance (as amended on 17/12/2013) (pdf).
• October 2013: Permitted Development for Householders - Technical Guidance (as amended on 20/11/2013) (pdf).
• October 2013: Permitted Development for Householders - Technical Guidance (as amended on 29/10/2013) (pdf).
• January 2013: Permitted Development for Householders - Technical Guidance (pdf).
• August 2010: Permitted Development for Householders - Technical Guidance (pdf).

The main differences between the current version (September 2019) and the previous version (April 2017) of the "Technical Guidance" document are as follows:

Larger rear extensions (pages 8, 17-20, and 23-25):

Part 1 Class A allows (subject to prior approval) certain houses to erect a larger single storey rear extension. For such houses, the rear projection limits (for a single storey extension) were increased on 30/05/2013 from 3m to 6m (attached houses) and from 4m to 8m (detached houses).

Several amendments relating to larger rear extensions have been made to the "Technical Guidance" document, as summarised below.

Firstly, on various pages of the "Technical Guidance" document, the previous references to the 30/05/2019 deadline have been removed. For example, on pages 8 and 17, the phrase "From 30 May 2013 [to/until] 30 May 2019" has been removed, and on page 17 the sentence "Works must be completed by 30 May 2019 and the local planning authority must be notified of their completion" has been removed.

Note: For info, prior to 25/05/2019, Part 1 Class A required a larger rear extension to be completed on or before 30/05/2019. However, on 25/05/2019, this Class was amended to remove the 30/05/2019 deadline (note: for more information, please view this previous post). In other words, these PD rights were made permanent.

Secondly, some of the advice within the "Technical Guidance" document has been moved from the section relating to limitation A.1(f) (which sets out the rear projection limits for a standard extension) to the section relating to limitation A.1(g) (which sets out the rear projection limits for a larger rear extension). For example, on page 18, the two paragraphs and two diagrams have been moved from the former section to the latter section.

Note: On page 18, the second paragraph and second diagram, which provide advice about how limitation A.1(ja) relates to limitations A.1(f) and A.1(g), remain confusing. The second diagram shows a proposed extension for which (in my opinion) 1) "the enlarged part of the dwellinghouse" would be contrary to limitations A.1(f) and A.1(g), and 2) "[the] total enlargement" would be contrary to limitation A.1(ja). However, the second paragraph, which primarily relates to limitation A.1(ja), only states that the proposed extension would fail because of "the enlarged part of the dwellinghouse" (i.e. limitations A.1(f) and A.1(g)).

Thirdly, in the previous version of the "Technical Guidance" document, several paragraphs and diagrams (in the sections relating to limitations A.1(g) and A.1(j)) primarily provided advice about standard extensions (with information about larger rear extensions provided in brackets). These paragraphs and diagrams have been amended so that they now primarily provide advice about larger rear extensions (with information about standard extensions provided in brackets).

Note: In my opinion, the fact that the above advice now starts by covering the minority of cases is potentially confusing. As an example, for an extension in the infill area between an original rear wall and an original side wall, the advice on page 23 (in the section titled "Rear and side extensions") now states the following [note: my emphasis in bold]:

"Where an extension fills the area between a side elevation and a rear wall, then the restrictions on extensions beyond rear walls and side walls will both apply (see also page 20). The extension must:
(i) extend no more than 6 metres beyond the rear wall, or no more than 8 metres in the case of a detached house (or no more than 3 metres beyond the rear wall, or 4 metres for a detached house on article 2(3) land or sites of special scientific interest),
(ii) be a single storey and must not exceed 4 metres in height;
(iii) have a total width that does not exceed more than half the width of the house (measured at its widest point)."

In my opinion, the above advice could potentially give members of the public the incorrect impression that the 6m/8m rear projection limits apply in the majority of cases - i.e. in all cases except 1) article 2(3) land, or 2) a Site of Special Scientific Interest (SSSI). In fact, these limits apply in the minority of cases, because they also don't apply unless 3) the applicant has successfully completed the prior approval process. Similarly, on pages 23 and 25, the diagrams now show extensions with length 5m or 6m as permitted development, without reminding the reader that the applicant must successfully complete the prior approval process.

Note: Some of the above diagrams have not been updated properly. For example, in the first diagram on page 19, the length of each of the 3 extensions has now been increased to more than 3m, but the arrows and annotations for this diagram still correspond to the previous length of 3m.

Other (insignificant) amendments:

• On various pages, the references to "Department for Communities and Local Government" have been updated with references to "Ministry of Housing, Communities and Local Government" (note: this government department was renamed in January 2018).
• On page 4 ("Introduction"), the links to MHCLG's "Planning Practice Guidance" have been updated from the "http://planningguidance.communities.gov.uk" website to the "https://www.gov.uk" website.
• On pages 4-5 ("Introduction"), the description of Part 3 Classes M, N, P, PA, and Q has been updated to add a reference to "hot food takeaways" (note: Part 3 Class M was amended on 25/05/2019 to allow a change of use from A5 to C3). In addition, the previous phrase "from 1 October 2017 to 30 September 2020" has been removed (note: it's not clear why this phrase has been removed, as Part 3 Class PA still requires the "prior approval date" to be before 01/10/2020).
• On pages 8-9, 29, 34, and 44, (some of) the phrases "[Parts / Part 1 / Class A] of the rules" (or similar) have been replaced with the phrases "[Parts / Part 1 / Class A] of the Order" (or similar).
• On pages 10, 33, 38, 40, 41, 47, 48, and 49, in the wording of the limitations relating to Part 3 Classes M, N, P, PA, and Q, the phrases "be virtue" and "Part 2" have been corrected to the phrases "by virtue" and "Part 3" (respectively).
• On page 11 (relating to A.1(c)), the phrase "the part of the house enlarged" has been replaced with the phrase "the enlarged part of the house".
• On page 17 (relating to A.1(g)), the sentence "... the extension must not be more than 4 metres high" has been replaced with the sentence "... the total height of the extension must not be more than 4 metres".
• On page 17 (relating to A.1(g)), the previous paragraph reminding the reader about limitation A.1(b) (i.e. the requirement that not more than 50% of the original garden is covered by buildings) has been removed.
• On page 17 (relating to A.1(g)), the sentence "... a neighbour consultation scheme for the impact of the proposed development ..." has been replaced with the sentence "... a neighbour consultation scheme to assess the impact of the proposed development ...".
• On page 17 (relating to A.1(g)), the phrase "if a detached house" has been incorrectly replaced with the phrase "if a detached house".
• On page 17 (relating to A.1(g)), the previous paragraph about limitation A.1(ja) has been removed (note: this advice has now been incorporated into the similar paragraph about limitation A.1(ja) on page 18).
• On pages 17, 20, and 43, the phrases "two metres", "three metres" and "four metres" have been replaced with the phrases "2 metres", "3 metres" and "4 metres" (respectively).
• On page 19 (relating to A.1(g)), in the second diagram, the annotations "3m", "6m", and "9m" have been added.
• On pages 22-23 (relating to A.1(j)), the sentence "Any extension ... can only be half the width of the original house" has been replaced with the sentence "Any extension ... can not be more than half the width of the original house".
• On page 23 ("Rear and side extensions"), the sentence "... does not exceed more half the width of the house ..." has been corrected to the sentence "... does not exceed more than half the width of the house ...".
• On pages 23-28 ("Rear and side extensions"), in each of the diagrams, the annotations "... half width of original house" (or similar) have been corrected to the annotations "... half the width of the original house".
• On pages 26-28 ("Rear and side extensions"), in each of the diagrams, the annotations "... (measured at widest point) ..." have been corrected to the annotations "... (measured at the widest point) ..." (note: the equivalent annotations on pages 22-25 have not been corrected).
• On page 28 ("Rear and side extensions"), the phrase "(it does not join it)" has been replaced with the phrase "(as it does not join it)".
• On page 29 (relating to A.1(k)), the sentence "A 'Building' - includes any structure or erection ..." has been replaced with the sentence "A 'Building' has the meaning set out in the 'General Issues' section of this document and includes any structure or erection (see page 6) ...".
• On page 30 (relating to A.2), in the wording of limitation A.2, the word "or" has been moved from the end of A.2(b) to the end of A.2(c) (note: on this page limitation A.2(d) is still incorrectly shown as limitation A.2(ca)).
• On pages 37, 39, and 48, several references to other pages (e.g. "at page 32" , "see page 36", etc) have been added.
• On page 41 (relating to Class E), the word "nor" has been replaced with the word "or".
• On pages 41, 48, 49, and 50, in the wording of Class E, limitation G.1(b), limitation H.1(d), and condition H.2(a), a missing ";" (semicolon) has been added.
• On page 42 (relating to E.1(c)), in the second diagram, the annotation "Walls forming principal" has been corrected to the annotation "Walls forming principal elevation".
• On page 43 (relating to E.1(f)), in the diagram, the annotation "2.5ms" has been corrected to the annotation "2.5m".
• On page 44 (relating to A.1(h)), the sentence "A raised platform is defined as any platform that has a height of more than 0.3 metres (see page 6)" has been replaced with the sentence "A raised platform is defined in the 'General Issues' section of this document, as any platform that has a height of more than 0.3 metres (see page 6)".
• On page 44 (relating to E.2), in the wording of limitation E.2, an extra "," (comma) has been removed.
• On page 47 (relating to Class F), the wording of limitation F.1 has been corrected by adding the text "F.1", and the wording of condition F.2 has been corrected by replacing the text "F.1" with the text "F.2".

Additional notes:

• All links on the Planning Jungle website to the "Technical Guidance" document have been updated to ensure that they link to the current version of the document (i.e. the "September 2019" version).

Comments by the Planning Jungle website:

• In my opinion, this updated version of the "Technical Guidance" document is another missed opportunity by MHCLG. Despite the fact that this is now the 9th version of the "Technical Guidance" document, it still doesn't resolve a number of significant ambiguities within the legislation that even government Inspectors are unable to interpret consistently. For example, almost 11 years after the legislation came into force (on 01/10/2008), it's still not possible to give a definite answer to the simple question "is it permitted development (on a typical house) to replace timber windows with UPVC windows?".
• MHCLG could have identified most of these ambiguities by talking to Inspectors (or by referring to the documents on this website), and then could have taken the opportunity to resolve them via this updated version of the "Technical Guidance" document. Instead, most of these ambiguities still remain.