Do I need building regs or planning permission for external render
Do I need planning permission for cladding or rendering my house walls?
Do I need to follow building regulations for rendering if my house is listed or in a conservation area?
If you are replacing or applying 25% or more of the surface area of your exterior render or applying any other wall cladding to the exterior of a dwelling then you require Building regulations approval. Basically what they (the government) want you to achieve is improved thermal properties to the walls (or Envelope as they like to call it).
Other factors could mean you don’t have to do it for instance if it’s not technically feasible all this is a bit of a grey area see the condition on page 23 of the Part L1b PDF link below, they may allow a relaxation on the thermal efficiency of a building if its build is not suitable i.e. weight load factors.
This is not the case if the walls are just to be painted, cleaned (classed as decorating) or pointed, but you may still require permission for the colour if you are in a conservation area, its best to check and get something in writing before you do anything.
If your house is grade 2 or grade 1 listed or in a conservation or National Park then the appropriate local authority will deal with the building regs, your project may still have to have incorporate thermal improvements, they will take into account the building style and assist you in this matter.
Suggested reading download the PDF Part L1B see sections 54 55 and 57 also table 5 all on page 23 for more details.
Failure to comply with this law a fine of up to £5000, both contractor and homeowner can be accountable so don’t ignore this law.
Links to the government web site
http://www.planningportal.gov.uk/england/government/buildingregs/