Computing value of roof airspace above flat to extend

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    Computing value of roof airspace above flat to extend

    I live on the top (4th) floor of a converted Victorian building and want to extend my (leasehold) flat by adding a new (5th) floor above my current
    flat. My leasehold agreement states that in order to proceed, I should
    apply to the freeholder to seek their permission and 'such consent is not
    be unreasonably withheld'. I plan to live in the flat afterwards if the
    extension goes ahead.
    As I am doing this for the first time, are there any pitfalls I should look out for and how do we arrive at a 'value' for the roof airspace into which I would build if permission were granted by the freeholder? Are there
    different ways of computing this value?

    Assuming the property is in England or Wales.

    As this is your 'first time' and you don't mention that you have any bulding skills / knowledge then I strongly suggest you speak to a Professional. There are plenty of competent Building Surveyors, Structural Engineers, Architects and Architectural Technicians who can provide advise on what is and isn't acheivable.

    If you have a lot of time on your hands and can dedicate it to the project, then you can do a lot of things yourself. The cost will be primarily your time but if you cause delay to the builder (ie you made an error or you change your mind) then be prepared for additional costs.

    Some Builders do offer a design and build service but you tend to pay a premium for it. By design and build I mean proper design, sorting the necessary consents etc.... not 'we'll square it with Building Control.

    You'll need to cover a big list of things;

    1. Planning Consent - Flats do not have permitted development rights so any extension will require Planning Consent. Planning Department, Local Council.
    2. Building Regulations - Completely separate to Planning. The two are (for ease of explanation) not connected. Usually Building Control, Local Council.
    3. Party Wall Act - As you are most likely altering the existing structural dynamic of the building (and neighbours if it is terraced / attached) then you'll need to serve valid Notice on all effected Adjoining Owners (neighbours, freeholders). This could work out very expensive if it is a terraced block of flats.
    4. Freeholders Consent - You'll need to cover the costs of getting this. Part of it will [should] be that all statutory consents are in place.
    5. Alteration of the lease - again you'll bear the costs of this.

    As for the purchase of the loft area. That depends upon a number of factors. Is the loft space only accessible from your demised space? What is the increase in value of the property likely to be? What the build costs are? What does your lease say about altering the demise?

    You need to start at the lease and work from there.

    Your immediate plans for the property have no bearing on the valuation.

    Generally speaking the Freeholder will expect a share of the 'profits' of any extension. This is the increase in value of the property minus the build cost. So, if it costs £30k to complete the works and the flat increases in value by £50k then the Freeholder may ask for 50% of the £20k profit.

    The Freeholder is right to expect any payment before works start.
    There is always scope for misinterpretation.

    If my posts can be interpreted in two ways, one that makes you feel angry and one that doesn't, I meant the latter.

    Everyday is an opportunity to learn something new.


      Don't forget to measure / test the joists above your ceiling, as they
      will / maybe only strong enough to tie the walls apart, and not
      thick enough to support any loads, such asFurniture / beds etc etc.

      Any plans you draw up, ( which is a must ), the freeholder can
      get his own surveyor to inspect your plans, inspect the roof, and
      charge you the total cost of his surveyor, on top of your own.

      Don't be surprised if the freeholder wants to transfer the maintenence
      of the whole roof and exterior of the roof to you.
      And, the condition of all the roof beams will have to be inspected,
      and put right if any rot, as once you do the conversion, you wont
      be able, any more, to inspect all timbers when you have put your
      plasterboard over them.

      Just things to look out for, or to discus prior to conversion.


        This consent can be withheld. The freeholder is under no obligation to sell you the airspace or loft space and you cannot force his hand. The foundations will also need to be checked to see if the building can support a 5th storey.


          Not only that - is the local planning authority likely to give you consent. You will need to apply for full planning permission.

          I think bbva is in the right area!

          Freedom at the point of zero............


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