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Planning permission is required for around 40% of the conservatories we construct, however it rarely presents a problem other than a small time delay.
The determining factor is often whether your property has sufficient "Permitted Development Rights." These may have been used up if the property has been extended since 1948. In the case of many new homes, where house builders have been less than generous with the garden space, the rights may have been removed as a condition of the original planning consent.
Certain restrictions also apply to Permitted Development, we can advise you on this, click here to download a guidance leaflet, or contact details for your local planning department can be found at the bottom of the page.
There are also many local "conservation areas" where permitted development rights have been removed or reduced. Generally the emphasis is on the design and materials used matching the existing building, which presents no problem to us.
In either case we are able to take care of the planning application free of charge, as long as we get to build the conservatory! The target time for planning departments to deal with applications is eight weeks, as laid down by central government, however this does tend to vary between different local authorities.
Once we have submitted the application, we are normally able to book a job to start around the time we expect permission to be granted. This means that you do not have to wait for permission, and then go to the back of the queue. However, we are not quite able to get planning permission one day, and then start the next!
Building Regulations (Building Control)
At the present time, most conservatories are not required to have building control approval, subject to various conditions. The two most important ones are that the internal floor area is less than 30mē, and the conservatory is separated from the main building by external type doors.
We regularly build conservatories that are subject to building control. As this is a still a bit of a rarity, we often find that we have more experience in this area than the building control officer! The difficulty and cost this imposes varies between local authorities and can be a little unpredictable. However, in all the projects of this type we have undertaken, it has been well worth the hassle. For pure conservatory "wow factor," nothing beats having it fully open to the house.
The first obstacle in getting building control approval is meeting the insulation targets, which have been quite rightly raised in recent years due to concerns over global warming. As most conservatories have a higher ratio of glass to brickwork than the typical dwelling, we have to compensate by using glazing of a higher standard than required in house windows. Additionally, we have to use floor and cavity wall insulation of an above normal specification.
Depending on the conservatory design (more walls make life easier!) and type of house, the above measures may still not be enough. The next step is to undertake SAP (Standard Assessment Procedure) calculations, a method of determining energy use of the building overall. This may involve additional work such as increased loft insulation in the main building to offset any extra heat losses from the conservatory.
The other issue that arises is foundation depth. On all our conservatories, regardless of whether building control approval is required or not, we dig to a minimum of 1000mm (one metre) for footings. The raising of modern standards means that conservatory foundations are often deeper than those on the existing house.
Normally, one metre footings are fine, but it does depend on the site conditions. The main problems we encounter in the local area are the combination of high-shrinkage clay, large trees that consume a lot of water and "brownfield" sites that have all manner of things below the ground. However, if your ground is stone or chalk, or there are no large trees in the vicinity, it is unlikely to be an issue.
When building control become involved, they tend to err hugely on the side of caution. As there is no separate category for conservatories, the foundations have to be suitable for a two-story building. In the past we have had to dig two metre (almost seven feet) foundations for a 600mm (two feet) wall!
The other method is to use mini-piles, steel columns that are driven into the ground about eight metres deep. This method is quicker, cleaner and easier when access is difficult than digging a deep trench for footings, and tends to become more economical when a trench depth of more than 1800mm is required.
In summary, obtaining building control approval might not always be straightforward, but it has always been worth the effort.
Listed Buildings
Conservatories on statutory listed buildings will require planning permission and listed building consent. The easy part of this is for us to build the conservatory to the approved design, using approved materials and techniques.
The design / planning process is not always quite as simple! The challenge is to marry the client's requirements with those of the planning officer. Normally both the client and the design and conservation team will have the same goal; to ensure that the extension will be in keeping with, and enhance the existing building. The trick is to get both parties to agree on how this is best achieved!
National Planning Portal
Click here for the National Planning Portal
Local Planning Department's Websites
Where possible we have tried to provide a direct link to the Planning Departments within each Council, however with ever changing internet sites this is not always possible! In such cases we have provided a link to the Council homepage.
Cheshunt, Broxbourne, Hoddesden
Chesham, Amersham, Missendens & Chalfonts
Berkhamsted, Hemel Hempstead, Tring
Hertford, Bishops Stortford, Buntingford
Radlett, Potters Bar, Shenley, Borehamwood
Beaconsfield, Gerrards Cross, Burnham, Iver
St. Albans, Harpenden, Wheathampstead and Redbourn