Sounds like quite an unusual situation! It can be tricky to manage this type of project because of a number of factors, which I can elaborate on if you wish. If you intend to carry out elements of work yourself this amounts to a self build project with specialist input, which is a very different story to a traditional construction project, which may be why your architect is not comfortable with it. At the end of the day most people want to do their job as well as they can and it's likely that his considered view is that his recommendation will give you the best result - one that he can feel is a job well done that gives you the best outcome he can manage. If you are planning to carry out elements of work yourself make sure that the time you will take to carry them out will fit in with the rest of the works that you are having done for you. Also consider if a skilled tradesperson carrying out those same works might do them much faster and if the speed would have an impact on the cost in a way in which you may not have factored in - for example if you have to rent somewhere else for a longer duration then it may not be cost effective to do it yourself if the money saved is then offset by having to pay more in other costs like rent... It is always best practice to get more than one quote, however, there are some instances when this can prove tricky due to the specialist nature of the work and the location. Also you need to ensure that you are comparing like for like. Builders come in many different shapes and sizes so you need to be confident that they are going to be able to carry out that particular work to the speed, quality and budget that you are happy with. I can't comment fully on plumbing and underfloor heating and if this is silly or not as I don't know enough about the job. I would say that underfloor heating is more efficient if it's set within a concrete screed and can use the thermal mass as a lag to heating and cooling. If it's a historic building with suspended timber floors then it may be that radiators are more appropriate. It sounds like your architect has attempted a value engineering exercise for you and perhaps you would find it helpful to discuss this with them in more detail. It sounds like there may have been some confused communication going on. I hope you manage to sort this out in your meeting.

Hi all, many thanks for the feedback and comments. The house came with something called certificate of location, it basically details the dimensions of the plot and roughly the house, mainly to ensure it doesn't encroach on the neighbours. I don't plan on making any extensions. My plan is to remove walls, make windows bigger, open up the second floor apartment onto the downstairs apartment. I think following your tips I will reeach out to architects and explain the situation and find out whether having plans drawn up for the existing structure is necessary. It's going to be an exciting project and I thank you all for the feedback.

Hi James, Very much depends on the size and type of project, specifics to the site and build etc, however lots of people tend to get builders quotes using only the approved plans and specification. The danger with this is the lack of detail and specifics to your project, and you can end up with significant variance in prices quoted. If you choose a builder this way you also have the risk of paying substantially more than the initial quote, and/or ending up arguing with the builder over costs & item quantities and so on, specifically because of the lack of detail and 'mis-understanding's'. Programme of Works - sets out what happens when, project duration, key stages, inter-dependencies and so on, and something you would agree with the builder. Basically a Gantt chart, and something a lot of small builders won't use, preferring to quote for example a build schedule of 12-16 weeks depending on the job/weather etc. Always worth using particularly when working with more than one contractor, and when you do use most builders should try to commit to it. Cost Framework - how the job's being priced; whether via bill of quantities, schedule of rates, fixed price quote, provisional sums for different/specific elements etc. Most builders will price as a fixed lump sum, and will often include in their quote provisional sums for different elements (eg, could be radiators/type, £m3 for extra depth of foundations reqd, specific door furniture etc). For the average extension (if there is such a thing), you should as a minimum aim to get a quote with a Schedule of Works. This lists the specifics of your project and your choices, for everything from windows to sockets & door furniture, includes a lot more detail and should be read/priced against in conjunction with the plans & specification. You can have this drawn up by a project manager/architect or surveyor, and the net result should be that you get more accurate/consistent quotes in and hopefully less surprises down the line (though you should always allow for contingencies, as its very rare that you won't have something extra/unforeseen to pay for). Site-specific issues, working times etc can be included in the Schedule of Works, as can addressing/highlighting any conditions of Planning. You can agree a payment plan with the builder, always in arrears, and the specifics of this can be included in a JCT Minor Works Contract, which you can purchase online from RIBA. If you're unsure or don't feel confident dealing with these aspects, you should always get help, and particularly if you ever have any doubts regards payments against valuations/work completed. Other issues you will have to contend with include the CDM (Construction Design & Management) Regs 2015, and possibly Party Wall matters if applicable, and you can get lots of info about these online. It all sounds a lot scarier than it actually is, and you may feel a bit more confident once you research further. Hope this helps!

I cant figure out how to send a private message either! £15k on interior design / space planning alone was our budget for a 5 bedroom house refurbishment - I would say that ours definitely isnt ’light touch’ though - we get everything from the from the paint specification to a shopping list for every room and then a styling trip to come and do all of the finishing touches. Every room has everything from the floor covering to the window treatments to the files and designs for bespoke furniture. All rooms come with proffesional lighting plans, which can be handed over to an electrician. We paid around £3k for the structural engineer and £1k for the architect. We managed the project ourselves, so I dont have a comparison for that element i’m afraid but I certainly dont think that number looks unreasonable. I would definitely find out exactly what you are going to get for that money but honestly, presuming that the house is of significant value and your build cost is also significant (clearly important for spend to be relative) then that doesnt seem to be an unfair cost to me. Getting your space planning and interior design right, is a massive part of any project and can vastly change the look and feel of the finished house. We’ve all seen examples where people have spent A LOT of money on major reburbishments and the end result just looks a bit ’blah’ - its there in my opinion that an extra 5–10% of the overall cost would have completely transformed and ’polished’ the final result. Appreciate design is not possible for everyones budget but if its a possibility for you and you like the quality of their work, then I dont think that figure is out of the way.