Plans for extensions and alterations
Plans for your Hertfordshire extension, loft or garage conversion
Tell us what you want to build and where. With your consent, we pass your enquiry to a local architectural designer, if one covers your postcode, to talk through drawings and approvals.
- One form, one local designer, never a list
- Planning, Building Regulations and party walls explained
- Free to ask, and you decide whether to go ahead
This is an enquiry service. The designer quotes and agrees the work with you directly.
Drawing register
What drawings do you need?
- Drawing HEP-01About extension plans
Extension plans
Drawings for a rear, side or double-storey extension to your house, and what to check on planning, Building Regulations and neighbours before you build. Covers what the drawings include and when permitted development applies.
- Drawing HEP-02About loft conversion plans
Loft conversion plans
Drawings for turning roof space into a bedroom or study, and the planning, Building Regulations and party wall points that come with it. Covers dormers, hip-to-gable and rooflight conversions and the volume limits.
- Drawing HEP-03About building regulations drawings
Building regulations drawings
The technical drawings and details building control needs for an extension, loft, garage conversion or internal alteration, and how full plans and building notice differ. Covers what building control checks and what to do if work has already started.
- Drawing HEP-04About garage conversion plans
Garage conversion plans
Drawings for turning a garage into a bedroom, office or living space, and what to check on planning, Building Regulations and parking first. Covers parking conditions, floor levels and the front of the house.
Three overlays
How it works
General notes
Useful to have to hand
None of this is needed to send an enquiry, but it helps the designer understand the project sooner.
- Rough sizes or a sketch
Approximate room sizes, or a photo of a sketch on paper, are enough to start. The house can be measured properly later.
- Photos of the house
The walls where the work would go, and the loft space or garage if the project involves them.
- What you know about planning
Earlier extensions, whether the house is listed or in a conservation area, and any letters from the council. These can affect what needs planning permission.
- Shared walls and boundaries
Work on or near a shared wall or boundary may need a party wall notice to your neighbours under the Party Wall etc. Act 1996.
Location key · Hertfordshire
Areas covered
- Hoddesdon and BroxbournePostcode districts EN10EN11
- Cheshunt and Waltham CrossPostcode districts EN7EN8
- Hatfield and Welwyn Garden CityPostcode districts AL7AL8AL10
- StevenagePostcode districts SG1SG2
- RoystonPostcode districts SG8
- HertfordPostcode districts SG13SG14
- WarePostcode districts SG12
Not listed? Send your enquiry anyway. We only pass it to an architectural designer who covers your postcode, if there is one. More about the areas we cover.
Queries
Questions
Who will I be dealing with?
You will deal with a local architectural designer, if one covers your postcode. This website is an independent enquiry service and does not draw plans itself. The designer, not this site, agrees the scope and fee with you.
What if nobody covers my postcode?
We tell you, and we do not pass your details on. Your enquiry is only shared when a local designer covers your postcode, and only with your consent.
Do I need planning permission for an extension?
Sometimes, and sometimes not. Many house extensions can be built under permitted development, but flats, conservation areas, listed buildings and homes with removed rights are treated differently. Your local council's planning department decides, so ask it or apply for a lawful development certificate if you want certainty.
Is it free to ask?
Yes, sending an enquiry costs you nothing and does not commit you to anything. Any fee for drawings is agreed between you and the designer.
Who sees my details?
Only the one designer your enquiry is passed to, and only if you agree to that when you send the form. We do not sell your details to a list of firms.
Can I ask about work that is already under way?
Yes. Say so in your message. Drawings for Building Regulations can sometimes be needed after work has started, and the designer can tell you what applies.
Is Herts Extension Plans a design practice?
No. It is an independent enquiry service and does not draw plans. With your consent, it passes your enquiry to one local architectural designer, if one covers your postcode.