In the UK you will hear the terms First Fix, Second Fix and in electrical, third fix. In North America you’ll hear “roughing in” or in Australia the wet trade and dry trades. You may or may not come up against this, but it is best to understand what you are going to get if an electrician or plumber has priced to just do the first fix and you were expecting them to do the second fix too!
My husband used to be a site manager for a London developer and he studied electronics at uni, plus learned how to be a plumber when he got to the UK whilst working as a labourer. This means that we are pretty confident with small electrical and plumbing jobs that don’t need authority approval (building control approval in the UK). But to those of you who are renovating on a budget and are confident to learn a few things like how to change light switch plates (safely), you could do the “second fix” element yourself.
To be clear:
Second Fix (Trim Out) = Is where the connections are made to the visible things you see, such as the appliances such as sanitary-ware and radiators. Don’t forget if you are doing the second fix yourself to save money, make sure you still have someone such as a qualified electrician or an authority officer to sign off your work. You don’t want to be doing illegal work, so check this with your local authority and builder to see how far you can go on your own. Doing dodgy work (even if you don’t realise it isn’t right) can be dangerous and WILL devalue your property. If this isn’t an area you feel confident in doing yourself, then don’t. There are many other places in a project where you can save money, and I’ll show you them.
First Fix (roughing in) = Is to take the services such as electric (cables), plumbing (pipe work), AC & ventilation (duct work) to and from your new proposed locations. I included “from” because electrics are usually a ring (remember 8th grade science) and plumbing always needs a way to remove dirty water too. Its the “from” in plumbing that causes developers and renovators the biggest problems, so here are a couple of rules of thumb for you to consider when thinking about a new layout, especially when it comes to bathrooms and kitchens.
TIP 1: Whenever I’m designing a layout, I’l always consider the shortest route to the EXISTING riser (soil vent pipe). I would always weigh up the cost of installing a new pipe, especially if it involves ground works, as this can reveal a lot of costly surprises, especially in older buildings. My cost effective rule of thumb is to use what you have and find the shortest route to it, but if you can’t, get multiple quotes from people you trust straight away so you will know how viable your ideas are in terms of the costs on the project.
TIP 2: Always double check your pipe sizes with a local tradesman or even in a plumbing store. These pipe sizes should be checked against your equivalent of Building Regulations or authoritative body.
Here is a link to the UK Building Regulations for Drainage https://www.gov.uk/government/publications/drainage-and-waste-disposal-approved-document-h
Tip 3: My Rules of Thumb:
- A waste pipe from a toilet is 110mm diameter (about 4.3″). There is a very specific fall required for waste pipes so that the waste flows along with the water and doesn’t leave any “solids” behind in the pipe. So the water can’t flow too fast or too slow. The rule of thumb I use here in the UK is a fall of 1:40 or a 2.5% slope.
- A waste pipe from a kitchen sink or bath is about 40mm (1.5″) with a fall of 1:40 or 2.5% slope.
- A shower trap is different again its 40mm or 50mm (1.5″ – 2″) , but depends on the trap and the type of floor construction. Again I would try for 1:40 but your building control officer might allow a little less steep fall depending on the circumstances. The trap will usually take up more space than you expect – so always consider this in advance.
- A bathroom sink is different again! It’s 32mm (1.3”) and again, a lesser fall than 1:40 will probably be accepted by the building control officer, if you can’t get the required slope in.
TIP 4: WEDI (a company I use in the UK and Europe) have a built in tray and trap system that I use often whilst, working in high-end properties in London. The flow rate is really high for a shallow trap, so if you are struggling to get a really nice finish and yo udon’t have much room – this product is my designer tip! (P.S. no royalties here, just sharing my secrets with you!)