Home extension and CDM regs

patchyX2

I'm looking to do a fairly sizeable home extension (2 storey. New bathrooms, kitchen, plumbing, solar, and heating). Planning permission has been granted, and I'm going to try and find an architectural technologist to help draw up the necessary documents for a full plans building regs approval.

The thing that's thrown a slight spanner in the works is I've heard about CDM regs. As I understand it, I can either take the responsibility on myself, or I appoint a principal designer and principal contractor (or I could ignore it all entirely, but that sounds risky).  

I know nothing about the CDM regs, so taking responsibility myself doesn't seem like a sensible idea, and I imagine simply getting the builder and all other parties to sign something that says "I will adhere to CDM regs whilst onsite" is not sufficient.

So let's assume I need to appoint a principal designer (PD) and principal contractor (PC). The PD is straightforward as I'll just ask the architectural technologist. The PC is the tricky one. As I understand it, I'd have to ask the builder I appoint to act as the PC, and that makes him responsible for then managing and coordinating all trades on site.

I can imagine this last point being a massive sticking point for a lot of builders who are literally just that; they just want to build the house. They have one specialty. They don't have an army of other tradesmen on their books that they can call up and rely on. Even if I (as the client) knew a good plumber/electrician for example, I could ask the PC to use them, but the PC is still responsible for ensuring the CDM regs are met, even though it's nothing to do with them. I can't imagine there are many builders that would be keen for doing this unless you pay ££££££. The alternative I guess is to go with full blown construction firm with a project manager who will handle everything, but again that would be ££££££.

Am I missing something here? Keen to hear from anyone with experience in this area.

MysteryMe

You can make it a term of the contract that they adhere to CDM regs. A reputable builder will be aware of current regulations and adhere to them, it's in their own interests to work safely. Any builder who does extensions of that scale will be working alongside specialist trades all the time so they will be able to recommend such tradespeople.

casper_gutman

According to the HSE, "If a domestic client does not appoint a principal contractor, the role of the principal contractor must be carried out by the contractor in control of the construction phase." So, even if you don't explicitly appoint a principal contractor there will be one, as matter of fact, as long as there is some contractor controlling the construction (as opposed to you doing this yourself with only relatively minor involvement of trades with responsibility limited to specific aspects of the work). https://www.hse.gov.uk/construction/cdm/2015/principal-contractors.htm

Domestic clients' CDM duties are minimal overall, because the principal contractor (and there will almost certainly be one - see above) "must take on the legal duties of the client in addition to their own as principal contractor".
https://www.hse.gov.uk/construction/cdm/2015/domestic-clients.htm

gzoom

You are over thinking this. Contact a local builder and/or architect if you aren't sure. We had zero idea about building works before staring our renovations. All you essentially need is drawing for planning permission, these don't need to that detail but show main elevations. Construction drawings, these are what builders use to build from, and you may sell need a structural engineer involved. 

Actual building is done in stages, demolition of any existing structures if needed, grounds works for foundations, shell of the building, roofing, walls, insulation, all that gets you to 'first fix'. Than it's electrics, plastering, exterior finishing, interiors (kitchens etc). Each stage is generally done by different trades, but your main builder will have a team for each, unless you really want to project manage the whole thing in which case you can hire different trades for each stage.

Each stage needs building control sign off, your builder will have suggestions but also local council provides this service.

As for cost aim for £2000/sq meter as minimal, that figure can go much higher if you go mad on final finishing. If you want to save money be prepared to do work your self. The rule I've seen quoted and it was true for us, the final cost is likely to be double what you initial quote is.

Also don't discount the disruption to general life of having builders around the home, we moved out during the bulk of our build. 

I personally really enjoyed the process, but its not without stress, especially when 1 week in and the builder destroy what was perfectly good room. The last finishing bits can also break you, as we thought getting to first fix meant we were nearly ready to move back in....oh how wrong we were .

Our renovation works were pretty extensive, originally we told it would be a 8 month project, ended up taking 18 months. The final all-in costs were about 5 (five) folds higher than our original guesstimate before we engaged any one.

Design/quality, speed, cost, choose two of those three to prioritise as you cannot have it all!!! Good luck with project, people say moving house is stressful......I would say renovations of the home isn't far behind if not more stressful, but once you get to end it's an life experience you will never forget!!