Changing the tax regime can change behaviour pretty fast. There’s an entertaining blog entry on how taxation has affected housing design in some unusual ways. I love the Camelback houses in New Orleans. I did wonder why houses were so narrow in Amsterdam. On a more current note, it seems that some small residential development companies may be finding innovative ways to avoid CIL. A self build exemption is available to anyone who builds or commissions (my italics) their own home for their own occupation. Perhaps not surprisingly, there are stories of developers of small in-fill sites structuring development projects so that pre-sales are ‘commissioned’ by ‘self-builders’. For a 100 square metre dwelling assuming CIL at £200 pre square metre, that’s a ‘saving’ of £20,000. We can’t be sure how the ‘saving’ gets divided between the developer, the land owner and the home buyer, but we can be sure that little of it is being contributed to providing benefits to the wider community or countering the negative impacts to the community of new development. This might involve a significant loss of revenue for local authorities that have lots of windfall sites. I really don’t know how widespread it is. It would be interesting if an attempt were made to apply such a powerful tool to encourage an improvement in the environmental performance of the residential and commercial building stock. I suspect that Energy Performance Certificates would become very important to home buyers, sellers, landlords and tenants if Council Tax and/or Stamp Duty were linked to energy performance in some way.