What does First Fix really mean?

[ToughButterCup]

With all our recent alarms and excursions, trips round the desert [insert your own cliche] I have not been thinking too far ahead. But, now we are able to plan a little way ahead. To first fix.

 

What does first fix mean?

 

I have done a few hours reading based on this search, and elsewhere; this YT search is useful

 

I'd like to collate your responses into a simple list.

 

One bit of reading about First Fix points to the contest for space in the gap between ceiling and floor. MVHR ducting seems to come out on top.

So maybe an ordered list would add value: scheduling is a persistent self-build nightmare.

 

[ProDave]

Drain runs first, they have to go in straight lines and downhill so have first grab at available space.

 

MVHR runs next. They don't need to go up or downhill but take a lot of room.

 

Normal pipe runs next.

 

Electric last. Cable bends easily and does not mind taking a more tortuous route to go around all the other more fussy stuff.

[dogman]

Anything before the plasterboard

[jack]

47 minutes ago, ProDave said:

Drain runs first, they have to go in straight lines and downhill so have first grab at available space.

 

MVHR runs next. They don't need to go up or downhill but take a lot of room.

 

Normal pipe runs next.

 

Electric last. Cable bends easily and does not mind taking a more tortuous route to go around all the other more fussy stuff.

 

Yep, exactly this. Drain runs can be hard enough even going first if they haven't been planned in advance.

[Dudda]

I’ve tried to put them in order:

Soil Pipes, Waste pipes, Copper pipes, MVHR Ducts and cable trays together or at least coordinated, Hep2O pipes, backing / support pieces (eg for TV’s or WC cistern in stud walls), electrical back boxes, cables, door frames (if going for shadow gaps only otherwise later).

[Lesgrandepotato]

It means knowing much more about where stuff is going than you ever imagined, and at a detail level previously unconsidered. 

 

Do you have a detailed lighting design? you are going to need one, 

Do you have a detailed kitchen design? you are going to need one, 

Do you have a detailed bathroom design? see above...

Do you know where the outside tap(s) are going? will it be hot and cold? see above... 

[Declan52]

Don't forget to put a few empty conduits in place that should you think of something else when the build is finished or a new type of all singing dancing cable is invented then you sorted.

 

[ToughButterCup]

Not easy is it?

 

And what's a

1 hour ago, Dudda said:

[...]

shadow gap(s)

[...]

 

 

[Bitpipe]

For me, FF is everything before the cavity is closed with PB.

 

Broadly agree with the services priority above but rather than taking a strict linear approach, after doing some preliminary planning for each set of services, we got the electrician and plumber (boss) on site at the same time and did a walk around of the site identifying any places where there would be a contest for space (I represented MVHR ) and we agreed alternative routes for a few things to make life easier all round.

 

Because of steels, etc, we had a few 'highways' where lots of services needed to run but it got figured out in the end. MVHR can take up a lot of space if you have a high concentration of ducts coming together and the required bend radius can be a challenge - a poorly placed soil pipe can really bugger your plans.

 

What you want to avoid is giving one trade carte blanche to do what they want and leaving the follow-on trades to figure out how they can live with what has gone before.

 

Of course, if you have a detailed mechanical plan for all services prepared at the drawing stage then you can ensure that your construction has been designed to remove as many conflicts as possible - however these can be expensive to prepare so not everyone does it (and not every trade follows it) - plus you may change your mind about some things as the true internal shape of the house comes together - I know that our ensuite bathroom layout was constantly evolving until first fix commenced.

 

Other things to consider - 

Data & AV requirements

- cat 6 cabling for entertainment, media and old fashioned networking (computers, printers, wifi repeaters etc..). Don't rely on wifi to connect everything - if something is unlikely to move (TV, printer, workstation, STB, xbox etc..) and it supports wired ethernet then put a hard wired connection in - especially if its a high bandwith and delay intolerant service (like video).

- Ducts for HDMI cables - we have a TV and media cupboard with trunking in the wall between them to avoid cables on the wall

- speaker cables for surround sound (consider new innovations such as Atmos, 7.1 etc..)

- Telephony (super old school but handy to have)

 

Socket location for occasional or seasonal use like hoovering / ironing / xmas tree lights) etc. Guarantee is that however many 13a sockets you make provision for, there will always be one missing right where you need it.

 

Double check your door opening orientation and make sure your light switches are in a logical place.

 

Security system (sensors, alarm unit & keypads)

Security video (perhaps use cat 6, is PoE a requirement?)

Doorbell / Intercom / access systems (esp. if there are gates to be opened)

Electric UFH power and control -( a last minute decision for us, had to pop some already tacked boards off over a weekend to make provision)

Heated mirrors in bathrooms

 

Drawstrings if the ducts are not dead straight (even if they are), always amazed at how hard it can be to thread a relatively stiff cable down a duct without it getting stuck. The old bit-of-sponge-tied-to-fishing-line-and-sucked-through-with-a-hoover trick is very useful. 

 

Noggins/ply for wall hung items such as mirrors, sinks, TVs etc - unless you are using fermacel or are plying/osb the whole wall. Double check the furniture measurements too - I totally cocked this up for bathroom sinks as I didn't check where the fixings actually were and despite putting in a huge noggin, only just caught the top of it.

 

Pocket door frames.

 

Support for stairs & banisters if fixing to wall is required. We had to rip out a slice of the hall wall, reinforce and re-plaster after realising that our chosen stairs were effectively cantilevered on one side and needed substantial support. 

 

Another part of FF that I forgot to budget for was joinery to enclose pipes, ducts, cisterns etc that sat proud of existing cavities in the studwork - turns out there was a lot to do there.

 

Top tip - measure everything you ever want to find (or avoid drilling into later) and mark the dimensions clearly with a sharpie, making sure you allow or discount for FFL. Then photograph everything. Then photograph it all again and once more for good measure. Maybe take a video too and pan around.

 

Can't count the number of times I have consulted these images to check what's where. Inevitable the detail I really want to see is just out of shot. Luckily our electrician is practiced at his and I've called him for help finding something totally unrelated

 

I need a cup of tea and a lie down now - this thread has resurfaced a lot of trauma...

 

 

 

[jack]

26 minutes ago, Bitpipe said:

Top tip - measure everything you ever want to find (or avoid drilling into later) and mark the dimensions clearly with a sharpie, making sure you allow or discount for FFL. Then photograph everything. Then photograph it all again and once more for good measure. Maybe take a video too and pan around.

 

Can't count the number of times I have consulted these images to check what's where. Inevitable the detail I really want to see is just out of shot. Luckily our electrician is practiced at his and I've called him for help finding something totally unrelated

 

This, this and this. We took hundreds of photos, and they've been incredibly useful. Even so, I wish we'd taken more - a full set as soon as the studwork went up, and another set after each trade finishes (or periodically if they're all working at the same time). You mention your electrician - oddly enough, our electrician was obsessive about this (he's the one that encouraged us to do this) and took a lot of his own photos. Occasionally, the ones he's taken have shown the relevant bit that we've missed or had a poor angle on.

[ProDave]

A bit of "thinking ahead" is also worthwhile.

 

E.g  in my house in the upstairs bedrooms I have left a short run of floor board adjacent to each end wall as a "trap" i.e not glued down, just screwed down with enough clearance that they can be lifted later on.  These will allow me if required to fish new cables across the ceiling of the room below at any point.

 

It should also be possible to drop new cables from these traps down into the end wall service void of the room below, and down into the AV / media cupboard under the stairs.

 

The theory being when the next nee fancy AV connector comes out to replace hdmi then I can pull through the required cable from the av cupboard to the televisions in the main rooms.

[ToughButterCup]

48 minutes ago, Bitpipe said:

For me, FF is everything before the cavity is closed with PB.

[...]

I need a cup of tea and a lie down now - this thread has resurfaced a lot of trauma...

 

Debbie's making you one.  (Too late, it's writ  now .... )

[Bitpipe]

14 minutes ago, ProDave said:

 

The theory being when the next nee fancy AV connector comes out to replace hdmi then I can pull through the required cable from the av cupboard to the televisions in the main rooms.

 

Just cut the ends off the old HDMI and use it as a fancy drawstring

[HerbJ]

+1 to everything that's been outlined above.

 

It is all about detail planning, detail planning and more and more, if this work is completed early in your design stage, it can save you a lot of money, time and frustration.

 

Depending on your house construction, it's not just about the internal fit-out before PB. The same issues are also relevant for the external fit-out, especially if you timberframe with cladding or rendered external finish.  It's critical that you plan and make provision for supporting anything with any weight fixed to the external skin - satellite dishes, aerials, rainwater goods, balconies,  fence posts, etc

 

Penetrations of every variety are also critically important to plan and make the necessary provisions.  Properly engineered collars in RSJ's to enable installation of MVHR ducts, pipes and even electrical cables ( see photo).  Penetrations in external walls (for boiler flues, electrical and water services etc)  before insulation is installed. This particularly important for a MBC type timberframe with blown cellulose insulation  and for achieving an airtight construction.

 

If you are installing wet rooms or similar, then it is important to review your floor joist locations and orientation in detail, to ensure that you install the shower waste and associated piping.  My wife and I spent hours looking at the detail and moved several floor joists. However, we didn't consider the MVHR duct installtion in detail at the same time and it created a problem with a clash in one location, which we just got away with with some minor adjustment and some rework.

 

 

 

 

Edited November 8, 2017 by HerbJ
to finsh post

[PeterW]

Don’t forget your sound insulation too ....

[Jeremy Harris]

1 hour ago, PeterW said:

Don’t forget your sound insulation too ....

 

 

I found that stud wall sound insulation was best fitted as the guys were boarding up.  If one side of a wall is boarded, it makes it a lot easier to fit the insulation from the other side.  Part of this is because the gap in a stud wall is typically 89mm, and the insulation is 100mm thick, so it tends to be easier to just push it hard back to one surface then let it expand out a bit.

 

I went around with the plasterboard guys, waiting for them to finish boarding one side, then I'd fit the acoustic rockwool. 

[Simplysimon]

8 hours ago, recoveringacademic said:

Not easy is it?

 

And what's a

 

 

when two surfaces meet, it can be difficult to hide the join. putting the join in shadow disguises it. can be achieved by putting join at the top of a groove or rebate or underneath an overhanging bead. emphasise the join by making a feature of it hides it. 

[Visti]

Great breakdown of how to prioritize each of the jobs in FF, that's placed a few more line items into that phase of the plan with lots of important commentary in red so I don't forget!

[ToughButterCup]

Thanks everyone. I'll try to find time to  turn this thread into a checklist

[ToughButterCup]

Here's the draft checklist for comment

 

1.    Drain runs: must be downhill and straight
2.    Spare conduits: draw strings
3.    Soil Pipes
4.    Copper pipes
5.    MVHR runs
6.    Hep2O
7.    Electrical backing boxes
8.    Electricity cable
9.    Data and Audio visual: printer, HDMI cables, speaker cables
10.    Telephony
11.    Socket location
12.    Security
13.    Fire alarm
14.    Normal pipes
15.    Door bell
16.    Door frames
17.    Pocket door frames
18.    Stair well: floating / cantilevered?
19.    Leave floor boarding unfixed to enable new cables to be fished across
20.    Photograph everything,  measure and mark with a sharpie as needed ( but not on Plaster Board) and/or take notes. Make allowance for finished floors & walls.
21.    Sound insulation
22.    Plaster Boarding

23.    Support (noggins) for wall hung items such as cupboards, sinks, mirrors, TVs,

 

What have we missed out?

[Bitpipe]

Support for wall hung items such as cupboards, sinks, mirrors, TVs, etc. Either timber noggins, or ply/osb cladding unless a very heavy duty plasterboard is being used.

 

(updated , Ian)

[Bitpipe]

On 16/11/2017 at 13:37, recoveringacademic said:

Here's the draft checklist for comment

20.    Photograph everything

What have we missed out?

 

Not just photo but measure and mark with a sharpie and/or take notes. Make allowance for finished floors & walls.

(updated, Ian )

[ProDave]

Don't mark with a sharpie on plasterboard. You WILL curse when you try to paint over it.

(updated, Ian )

[Bitpipe]

To @HerbJ 's point above, make sure steels have penetrations spec'd at design stage. 

 

Soil pipes and MVHR are the largest services that need accommodating but even a cluster of insulated 22mm pipes or a run of cables to a distribution board can take up significant space.

 

Our downstairs loo ended up sitting above a perfectly boxed in square of steels over the basement which meant that the soil pipe had to go underneath them and get boxed in. Luckily not that noticeable.

 

You can make a feature of an awkward vertical pipe run - we have a faux 'fireplace' box that hides a dog leg pipe run on one side of the living room and a nice feature alcove that hides another.

[Bitpipe]

2 minutes ago, ProDave said:

Don't mark with a sharpie on plasterboard. You WILL curse when you try to paint over it.

(updated, Ian )

I meant on the wall/ noggins etc before the PB goes on.