Apart from the obvious hoops and hurdles to navigate when embarking on a project, there are many things that should be taken into account at the early stages, but quite often are not.

1. A critical first step is to understand the planning process and restrictions. Most loft conversions and extensions are allowed under permitted development rules without the need for a planning application, but must comply with strict rules. However, if your project is in a conservation area or linked to a listed building, you will need to secure a separate listed planning approval before proceeding with the work.
2. Always check the history of the house. Permitted development rules apply to all work carried out on the original building and so you may find that there are existing extensions already built which will reduce the amount you can extend by without having to apply for permission. A conservatory also accounts for part of that area as it is subject to the same rules as an extension.
3. Although you may not need planning permission, you will still need building regulation approval for any work of a structural nature (including underpinning), drainage, replacement windows, heating appliances or rewiring. Check if you need planning permission here.
4. If you have trees on the site, check to see if they have preservation orders on them, especially if you intend to prune, lop or fell any tree as a result of your project. 
5. You must also consider the neighbours. If the work is within a certain distance of a boundary or on the boundary line, then you may need to serve a Party Wall Notice on your neighbour to provide them with the opportunity to ensure that the works will not damage or undermine their own property. This is designed to protect both you and your neighbour and so if there is a disagreement, then the case will be passed to a Party Wall surveyor who will assess the impact of the proposals and issue an agreement which is then legally binding on both you and your neighbour.
6. There is also the issue of ‘right to light’ which does exist in law. The right to light is established by ‘prescription’, usually after 20 years of enjoyment (similar to an easement), but is relevant only in limited circumstances and usually only in dense urban areas where buildings are very close together. However, even if a right to light exists, it only provides for whatever light is reasonably required and does not prevent you from planning your project to suit your requirements, as blocking a view or reducing the amount of sunlight to a neighbour is usually a planning issue.
7. If your project includes a downstairs toilet, you may be surprised to know that you can now site them anywhere. Under previous regulations, you always had to provide a lobby between the toilet and other rooms (especially where food was being prepared), but now you can have direct access as long as they have a wash basin and adequate mechanical ventilation. This is also true for shower rooms, which can also be sited anywhere.
8. There is no minimum ceiling height for rooms in the building regulations. This has helped to open up more loft spaces for conversion, especially where you may have old king or queen post trusses that would have had to be cut through to achieve the required headroom in previous years. Now they can be left in place in all their glory. However, for practical reasons, any space under a sloping roof should ideally have at least 50% of the floor area at a minimum ceiling height of 2.1m, preferably at 2.3m.
9. With regard to costs, you probably will not be able to claim your VAT back. Nearly all extensions are subject to 20% VAT unless unless they meet certain conditions. If you are able to claim your VAT back, be sure to use a VAT registered builder as you cannot claim the VAT back yourself.
10. And the most important thing at the start of a project, is that there is a difference between an estimate and a quotation. An estimate is a contractor’s best guess at what your project is likely to cost and it doesn’t matter whether it is verbal or written, it is not legally binding and the final bill could be considerably higher. Whereas a quotation is a firm price and can be used in contracts and used to manage costs and expectations.

The above are just a few of the common oversights when embarking on a project, but with the right guidance and support, most hoops and hurdles can be navigated successfully to provide you with a new space that is both functional and value for money.