As well as using the list below, we also recommend you have a look at the building regulations section on the Planning Portal

Build a new building
You will need to make a full plans application or submit a building notice

Build an extension to a building
You will need to make a full plans application or submit a building notice

Build a conservatory or porch
You will need to make a full plans application or submit a building notice for a conservatory or porch unless it fulfils all of the following criteria:

• It has an internal floor area that is 30m² or less
• It is thermally separated from the existing house, i.e. there are external-quality doors or windows.
• It has safety glazing within critical locations to satisfy BS6206
• It is not sited below an escape window to a loft conversion
• Any heating provided within the conservatory should be controlled on a separate zone
• The area of glazing to the external walls is not less than 50%
• The area of glazing to the roof is not less than 75%

Build a small detached garage
Not if it's under 30m² and the garage is 1m from the boundary or it is of substantially non-combustible construction. Otherwise, you will need to make a full plans application or submit a building notice

Build a carport
Generally no, not if it's under 30m² and open on two sides. 

Change the use of a building
You will need to make a full plans application or submit a building notice

Convert a single dwelling to flats
You will need to make a full plans application or submit a building notice

Create a room or rooms in a loft (roof void)
You will need to make a full plans application or submit a building notice

Install, extend or change a drainage system for example, by adding a new bathroom or toilet
You will need to make a full plans application or submit a building notice

Install or replace electric wiring
From 1 January 2005 this work is covered under Part P of the Building Regulations. Unless you are doing repairs, maintenance work or making changes to existing circuits (except in a kitchen, bathroom or outside) you will need to make a full plans application or submit a building notice

Renovation
If you are replacing / renovating more than 25% of the surface area of a wall, floor or roof, an application may be required. This is due to the upgrading of thermal regulations. Please contact us for further information.

Replace a roof covering with a lighter or heavier material. For example, replacing slates with tiles.
If the loadings are 15% lighter or heavier, the roof structure and supports will need to be tied down (for lighter materials) or strengthened (for heavier materials). You will need to make a full plans application or submit a building notice

Replace windows, doors and rooflights
You will need to make a full plans application or submit a building notice unless the work is carried out by an installer which is registered with one of the following competent person schemes; FENSA, Certass Limited or British Standards Institution (BSI). From 1 April 2002, replacing glazing was included within the Building Regulations and you must now comply with strict thermal performance standards.

Structurally alter the inside of a building. For example, the removal of an internal wall or chimney breast
You will need to make a full plans application or submit a building notice

Structurally alter the outside of a building.  For example, creating a new opening for new windows or doors.
You will need to make a full plans application or submit a building notice

Underpin foundations
You will need to make a full plans application or submit a building notice

Building Control
Guildford Borough Council
Millmead House
Millmead
Guildford
GU2 4BB

Tel: 01483 444545
Email: buildingcontrol@guildford.gov.uk