Project Team RIPA
9 min readFeb 28, 2021

As mentioned in our two in one blog covering the two sprints to 26th February 2021 — this is a separate blog sharing the discussions with the Lambeth Planning Lawyer who answered some of our ‘edge’ type questions.

Our first question and the associated response is below:

1. Can a structure that is connected to the main house ever be an outbuilding?

The working assumption we have used so far is:

Physically to main building = extension, but standing separately = outbuilding.

However, in a scenario about converting garages, the question came up that perhaps a lean-to garage that does not have an interconnecting internal door into the house could be viewed as an outbuilding. Is this possible? If so, is there a better definition, and any case law on this?

Over the second sprint, time was spent looking at the Developer Trello board and rejigging some of the priorities so that we could edge more quickly towards our working mvp.

The answer to this first question was over a course of discussions and follow up emails– the main parts of those emails pasted below:

“In relation to Q1, the GPDO itself doesn’t refer to “outbuildings”, that is, it never uses that term (and nor would it ever be likely to do so, because it is a general non-technical term that could cover a variety of factual situations). For that reason, there is no reason to expect there to be caselaw on the definition of that term, certainly for the purposes of applying the GPDO, because there would be no need for the court to devise a definition of something that wouldn’t take the matter any further forward (because the GPDO doesn’t use that term).

The GPDO basically distinguishes between something that is an improvement or alteration to a dwellinghouse, and something that is a building within the curtilage of a dwellinghouse (i.e. a separate structure) and which is for a purpose incidental to the enjoyment of the dwellinghouse. The GPDO uses these broad categories rather than referring to things like sheds, garages or outbuildings. Garages, for example, could be entirely freestanding structures or they could be physically connected in some way to the dwellinghouse, either with or without a connecting door. Whether or not PP would be required and if so whether a PD right would be available would depend on what the person was wanting to do.

It is hard to answer this any further without knowing the context. Is someone writing a GPDO bot? If so, what is it that you are trying to teach the bot to do? What is the relevance of whether something might be thought of as an ‘outbuilding’, since this isn’t a recognised category for the purposes of the GPDO?”

We realized it would be easier for the Lambeth lawyer to talk on the telephone with the team — and following that discussion — further advice was duly emailed to us:

“The question that is being raised is whether a garage that is physically joined on to a house in some way should be treated as being part of the house for the purposes of the availability of PD rights, and whether it makes any difference to the answer to that question if there is an internal connecting door between the garage and the rest of the house.

Essentially, as noted below, this concerns how householder projects concerning extensions to garages should be treated for the purposes of the availability of PD rights in Part 1 of the GPDO, and in particular whether garages that are linked to a house via an internal connecting door should be treated as part and parcel of the dwellinghouse for the purposes of Class A of Part 1 or whether these should be viewed as ‘outbuildings’ and so liable to fall under Class E of that Part.

I remain of the view that I expressed in my telephone discussion on Friday, namely that if a garage is physically attached to the house, it should be treated for the purposes of applying Part 1 as part of the dwellinghouse, not as a structure that sits within the curtilage of the property. I am not aware of any caselaw on this issue, as I doubt it is the sort of issue that would end up being litigated. There is no commentary of relevance in the Planning Law Encyclopaedia. I don’t consider that the existence, or not, of an internal connecting door between the garage and the rest of the house is relevant to the question of whether the garage should be treated as forming part of the dwellinghouse. If you have a garage which is joined on to the house, either as an ‘integral’ garage that is seen sometimes in a townhouse-style development or in a split level property, or by way of a structure that extends from the house (usually of course at the side), then in my view the garage is part of the dwellinghouse for the purposes of Part 1, meaning that alterations etc would fall into Class A. This is so regardless of whether there is any means of getting between the house and the garage through an internal connecting door. I don’t see that a garage that is joined on to the side of the house but has no internal door linking it to the house (meaning it can be accessed only from the outside) is any less attached to the house than a garage which does have an internal connecting door. The addition of an internal door would not require PP (although it might require building regulation approval). To base the distinction between the application of Class A versus Class E rights on the presence or absence of something that could be changed without further ado and that itself is outside the scope of planning control, as opposed to something deriving from the physical relationship between the house and the garage, would strike me as a bit odd and not in accordance with the overall scheme and purpose of the GPDO. To go back to your original Q1, a ‘lean-to’ garage is still attached to the wall of the house, even if it has no internal connecting door; it doesn’t become an ‘outbuilding’ just because it has no internal connecting door.

There might I think exceptionally be cases where it would be necessary to decide whether a garage could be said to be attached to the house, for example if a garage was connected to a house not by means of being attached to a wall of the house but by means of some sort of covered passageway, which may or may not also have side walls. It may be that consideration needs to be given to how those should be classed. There might for example be a distinction between a garage that is connected only via a covered walkway, and one that is connected by a fully enclosed corridor.

If, by contrast, the garage physically is detached from the house, then it wouldn’t fall to be treated as part of the dwellinghouse for the purposes of Class A. Instead, it would be treated as a freestanding structure. Potentially, rights in Class E of Part 1 may be relevant when dealing with a detached garage that the householder wishes to extend or to alter. I should add that back in the day (by which I mean the GPDO as it stood in 1988) structures that were within 5 meters of the dwellinghouse were deemed to be included when working out the permitted tolerances for extensions when compared with the size of the original dwellinghouse, but those provisions have since been replaced by other ways of measuring the cumulative impact of extensions.

‘Dwellinghouse’ is not defined for the purposes of the GPDO, other than we are told what a dwellinghouse is not i.e. for these purposes it is not a flat. The courts have expressed the view that there is no need to define it, because it is obvious what it means. I don’t think that a dwellinghouse could be interpreted as meaning only the parts of a building that someone might conventionally describe as ‘the house’ or that would be described as ‘the house’ in say estate agent particulars. In land use terms, a garage is simply part of the structure which a person occupies and which (subject to any necessary building regulation approval and other constraints such as lack of natural light) they can use for whatever domestic purpose they wish, which could be anything from a utility area or a place to exercise or carry out hobbies, to a place to store items which may or may not include vehicles.

There is some support for the view expressed above in MHCLG’s Technical Guidance on householder PD rights. This says (p. 41) in relation to Class E that “Buildings which are attached to the house are not permitted under Class E (they would be subject to the rules in Class A)”. That supports the view expressed above that the relevant consideration is (purely) whether or not the structure is attached. The core question would seem to be therefore along the lines of “is the garage directly attached to the house or is the garage a detached building? If you’re not sure, please describe your layout”.

I had a quick look at Planning Resource but we do not have a full subscription. Again, the distinction in the reports of appeal cases noted there seemed as far as I could see to be between garages that are attached and those that are detached.

Trying to reduce all the sorts of situations that might in practice occur to the terms of a ‘flowchart’ for someone wanting to know whether they need PP is actually quite hard, as it forces you to really think about what is meant by each of the householder classes and to break down all the possible scenarios into ‘yes/no’ answers, which can sometimes prove difficult.”

Phew! Things are simply not simple in planning land.

Our second question for the Brains Trust was as below and came with a (relatively) shorter answer.

Q2. Can you alter chimneys, add solar panels etc as well as do work under Class C?

Clause C.1 (d) of Class C (Other alterations to the roof of a dwellinghouse) says the following:

(Development is not permitted if) it would consist of or include —

(i)the installation, alteration or replacement of a chimney, flue or soil and vent pipe, or
(ii)the installation, alteration or replacement of solar photovoltaics or solar thermal equipment

However these changes can also be made under various other classes, such Class B(part1) (roof extensions), Class G (Part2) (Chinmneys) and Class A (Part 14) (installation of solar equipment on a dwellinghouse)

So, the question is this. Does C.1(d):

A. Preclude those works no matter what class they are done under or

B. does it only preclude those works from being done under Class C, but without affecting your right to do them under other classes? That is to say, they are still allowed to be done alongside works that fall under Class C, provided they are done under those other classes, not under Class C.

If the latter is the case, it suggests that the purpose of C.1(d) is effectively just to say ‘if you’re looking to do any of these other things, you need to look elsewhere’.

And the answer provided is shown below:

The classes in the GPDO operate as development that is permitted by the particular class. You have to look at the requirements of the particular class to see what that class allows you to do, because the class may specify that certain things are not permitted by that particular class. This is apparent from the rubric used throughout the GPDO, which is to set up the broad description of development permitted by a class and then to go on to spell out if there are things within that broad category that are not permitted by that class.

So Part 1 Class C permits “Any other alteration to the roof of a dwellinghouse” [‘other’ in the sense of not covered by Class B of Part 1]. Under C.1, “development is not permitted by Class C” [emphasis added] in certain respects, including altering a chimney or adding solar panels. There are rights to make certain alterations to chimneys under Part 1 of Class G and to add solar panels to domestic premises under Part 14 Class A. So although Part 1 Class C does not permit a chimney or solar panels, there may be rights in other classes to do those things. It is then necessary to look at the requirements of those other classes, to see if the rights there are available.

Occasionally, the GPDO will specify that a right in a particular class is not available if a right in another class has been or is being exercised. For example, the right to extend a dwellinghouse in Part 1 Class A is not available if the right to use the premises as a dwellinghouse has only come about through a permitted change of use under another part of the GPDO, or if the dwellinghouse in question is constructed under rights in a specific part of the GDPO. The GPDO spells out the circumstances in which classes of permitted development rights have to be read in combination with one another.”

So — that resolved some of our more ambiguous questions that arose from our scenario testing — but there’s sure to be more to come, so watch this blog space…!



Project Team RIPA

We’ve made it to Beta. An MHCLG funded project, led by Lambeth with five partners — Buckinghamshire, Camden, Lewisham, Northumberland and Southwark