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Thoughts on DIYing plumbing


jamiehamy

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1 hour ago, Bitpipe said:

Our plumbing contractor (as used by Jack and HerbJ) did a more traditional radial layout for us with a hot return  - calculated all the flows and sized pipe accordingly, every bend allowed for -we reviewed his drawings before his guys started.

 

Their preferred material is copper but that does not work with pozi joists so they used straight runs of grey plastic (no idea what the proper name is) and we have connections in the walls & ceilings. Before completing 1st fix, they tested the system to 7 bar (we have an incoming PRV set to 3 bar) so some confidence that it will all stay good.

 

Copper tails where the pipes are visible and the whole boiler / heating / UVC plumbing in the plant room is in copper.

 

Across the whole job, it's interesting to see where the labour and experience was required.

 

Once the design was done and the run locations agreed, it was only a couple of days for two lads to carcass out the whole hot and cold network. As much effort was spent on the waste & soil pipes, getting the required fall in the space available (post MVHR install). Locating the Gebrit frames was also trickier than I expected, they need to be completely flush with the wall and have the necessary support. All the first fix work was very neat & tidy

 

Second fix (including shower trays) was a bit laborious, as much time drilling porcelain tiled walls to hang sinks and install showers as doing actual plumbing. Freestanding baths were a pain, both the sheer weight of them and the need to cut the tiled floor to make more space for the traps - this was an oversight on both our parts, I should have been more on the ball.

 

The final install of gas, boiler, UVC etc and commissioning of the whole system was a few consecutive days.

 

No major issues, aside from discovering that the tackers had put a screw through a cold cistern feed and a mix up between primary and secondary feed from Hansgrohe ibox - both were resolved quick enough and made good.

 

I guess most of the above can be accomplished through DIY but wondering what's the point where a professional must be involved? Will a plumber be happy to commission a system they have not been involved with and what happens if there are problems down the line?

 

 

 

 

 

I think that a lot  of DIY plumbing installs don't need a "professional" to commission, though.  In our case we have no boiler, an ASHP that doesn't require any paperwork, and the the same goes for the rest of the plumbing system; there are no items that need signing off, so a plumber never once crossed our threshold (just as well, as around here they are the most expensive of all the trades, by a massive amount - no offence to Nick!).

 

If you need certification for any installed equipment, like a UVC, boiler etc, then I can see your point, but if not, then why not DIY the whole job?

 

Plastic has de-skilled all the major work, and the only skills you really need to learn are working with copper pipe and fittings, which does require some skill and knowledge to do a good and reliable job.  If you weren't fussed about appearances and didn't have a boiler or UVC to have signed off, then you could quite easily plumb an entire house in plastic and not need much in the way of skills either.  Learning how to fit a plastic fitting properly, so that it will be reliable, takes most people at most half an hour, and there are no expensive tools to buy, just a fairly cheap plastic pipe cutter, a rule and a marker pen.

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18 minutes ago, JSHarris said:

Plastic has de-skilled all the major work, and the only skills you really need to learn are working with copper pipe and fittings, which does require some skill and knowledge to do a good and reliable job. 

 

No more is that evident than on a couple of local mass built estates near  me. I did a snagging visit on one recently and noticed things such as (as they used Speedfit) that the collars were not screwed closed etc and there were various places that the pipes crossed over each other for no apparent reason.

 

And don't get me started on the state of the insulation !!!!! Where it met a pipe clip, there was a gap.... Most of the "cuts" looked like a demented squirrel had gnawed at it, and the pipework in the attic - for no other reason than they didn't put it under a floor as it was just H&C to an ensuite - was insulated with 15x9mm.... I mentioned the water byelaws and minimum thickness and I was told thats how they always did it and no-one ever complained..! 

 

Suffice to say after a short exchange of emails with the UK technical director of said company, the insulation was fixed in around 40 houses....

 

 

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On the subject of insulation what's the norm for insulating where the pipe clip is?

 

Right or wrong I cut a neat square (with a small snap-off knife) out to go over the clip so everthing looks pretty seamless from the front.

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53 minutes ago, PeterW said:

Suffice to say after a short exchange of emails with the UK technical director of said company, the insulation was fixed in around 40 houses....

I wonder how many others they've built over the years failed to meet the standards!

 

Maybe the volume builders should be made to do recalls, a bit like the car industry. Might make them take more care!

Edited by Triassic
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4 minutes ago, Triassic said:

I did the same as you, but only insulated the hot water. I often wonder if pipe Insulation is necessary in a very well insulated house?

Sometimes the opposite. If pouring a glass of water do you want the water warm? That's why it's good to insulate the mains water in a well insulated house so you can get nice cool water at the sink without having to let it run.

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3 minutes ago, Triassic said:

I did the same as you, but only insulated the hot water. I often wonder if pipe Insulation is necessary in a very well insulated house?

 

My place couldn't be less insulated, it's dire. Part of me has put it off as I want to change the roof to gable ends.

 

That being said I can't see the point of heating areas where you don't want it. My feeling is you want the "heat" in that pipe to get to its final destination without leeching heat en route.

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6 hours ago, Dudda said:

The 'two things in the horizontal runs' are thermostatic mixing valves. Not sure of the black thing.

 

Not generic but attached is a drawing I did recently of the system I'm proposing following review of Nick's image. It's for the cold only. I haven't finished the hot system.

 

If anyone has any comments or suggestions let me know as I'm not a plumber or mechanical engineer and new to this.

Water.pdf

Do you have sufficient volume and head to not require a secondary pump for the rainwater?

Do you have filtration on the primary and secondary sides? 

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5 hours ago, Nickfromwales said:

Do you have sufficient volume and head to not require a secondary pump for the rainwater?

Do you have filtration on the primary and secondary sides? 

Ya the height is good and the flow is ok. The volume can't be large as it's not advisable to store large amounts of rainwater in Attic tanks as it can stagnante so it's only a 60 litre tank. I've only one toilet connected at the moment and it works well. Not sure how well the outside tap will work. The rainwater tank outside isn't complete yet but is a Kingspan compete system that comes with filters and pumps. The rainwater header tank in the Attic is currently filled by the backup mains as what will happen if the main outside tank is empty.

Still designing my hot water but I'll start another thread for that when it's done as I'd be keen to get input like yours.

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As I said in another post if I compare our 20-30 year-old plumbing in our current house and the HEP2O manifold system in our new house, they are truly a generation apart in terms of technology.  It's not just the materials, but the skills needed to do the latter are fundamentally different to the former. 

  • The old system was unpressurised, all in copper and loop-based so lots of solder joints in inaccessible places.  The only active components were manually operated taps.  In general this was very energy wasteful.
  • The new system is plastic / push fit radial so no joints within the building fabric; the system runs at a limited mains pressure and there are sensitive active components. A large amount of thought and planning has gone into achieving the overall energy efficiency.

The old system was a trade and the new a technology that requires a professional approach and a lot of the old trade skills are simply redundant.  

 

Yet I suspect a large number of plumbers (probably a significant majority, IMO) have yet to make this switch, so the consumer or self-builder might be very constrained by the skill set of his chosen plumber.  A friend of mine doing his own new-build is in exactly this situation: "old-school" plumber = old-school installation = expensive and energy inefficient.

 

In our case we can easily supply most of the skills and labour needed.  And in a lot of area such as layout planning, scheduling with other trades, component procurement we're probably a lot more skilled than the average plumber.  What we really need is a few days for high-grade professional services: to do the component selection for the active components and to review our design, and then at the back end to commission and test the completed system.  I'd happily pay double the going plumbers day-rate to get this sort of quality service, but it would only be for a few days so it would still make economic sense for us.  But for the true professional plumber, this is a very niche market.

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Although plastic pipe is very good in all respects, the de-skilling of the trade of plumbing does concern me (as does the de-skilling in a number of other trades).  We run the risk of proper plumbers becoming like the master thatchers that work a fair bit in our area, an old and rare set of skills that only exists to service older buildings.  The knock on effect we're already seeing.  We bought a brand new house once (never again!) and that had been built by a developer who'd used workers (I can't possibly call them tradesmen) who were pretty dire.  It had plastic plumbing that was a complete mess, with no pipe clips anywhere that I could see - they had just cable tied pipes together.  The lack of skill was evidence everywhere in the build, from the concrete floors not being anywhere near level to the step flashing around the chimney having been fitted with the overlaps the wrong way around (and, we found when getting the leaks fixed, no soakers fitted either).

 

A wander around any big development will show loads of poor workmanship, almost certainly because the big developers aren't prepared to pay the going rate for decent tradespeople, and I have a feeling we're probably building a generation of houses in big developments that will be lucky if they last 30 years, largely because of the way they are thrown together.

Edited by JSHarris
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Jeremy I slagged off plumbers for zip tying pipes but had interesting convo with a new build plumber last year. He says 1st fix work is inspected and it's how they win pride in the job awards. 

 

They use metal noggins which clip out to joist centres, always put the matting stuff between pipes and metal. Then use colour coded zip ties. I can't remember the full ins and outs but the way he explained made it seem a rational and near way of doing things. Not a bodge like I thought!

 

agree with general consensus about de skilliing though but it's happening to every trade. Look at underground drainage!

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33 minutes ago, Barney12 said:

Whilst we're debating plastic pipe.......

 

Whats the score with earth bonding now? When and where should it be used? 

Just on the gas I thought. 

Cant travel thru water pipework of interrupted by plaggy?

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5 hours ago, Oz07 said:

Can't <electricity> travel through water pipework interrupted by plastic?

Effectively no, mains quality what is a pretty poor conductor: good enough to electrocute you but not good enough to use for earth continuity.

 

On this main thread of DIY plumbing, this is a mix of design knowledge, techniques and skills and quality.  As Jeremy commented the building industry in the UK is dogged by poor quality.  I've worked in IT all my life and for three years my title was IT Operations Director for Rolls-Royce (the aero-engine one not the car one).  Now that is a company that has quality as part of its DNA and culture, and IMO pretty much at the opposite extreme of current practice in the building industry. 

 

In IT whether application development or IT services where I worked for the last 10 years of my career, there is still a good quality culture.  Processes and procedures were documented; testing and review were build in; essentially everyone was subject to independent scrutiny and accountable for there outputs.  Lessons learnt where aggregated up and fed back into improving the processes.  This was just part of the culture, and on the IT services side of my company I was at the top of that review and assessment pyramid in Europe.  It wasn't perfect but it was a different world away from what we see in the building industry today where individual tradesmen work largely unchecked and in isolation.

 

Now the average self builder will definitely not do as good a job as the top tradesmen, but IMO a best Q is to ask: with a small amount of advice and support (and sometimes testing / certification), will he or she do better than the average tradesman working to a rate that they can afford? And I think that the answer is "yes, definitely" for most knowledgeable self builders.  

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Just a quick update - we've been working flat out to get ready for the spark - coming on Thursday to start. Plumber got in touch - issue with his phone - just waiting on a price for the works, however he is happy with a manifold system for distribution. I am happy to do it myself,but 18months in, I'm willing to pay a fair price to have it done in a quarter of the time and far more professionally - hopefully his price is reasonable. 

 

@Nickfromwales - can I check - does the cold water go through a manifold system to keep pressure to hot and cold roughly the same?

 

And have you put a patent on your design as per the pic? ;) 

 

 

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4 hours ago, jamiehamy said:

can I check - does the cold water go through a manifold system to keep pressure to hot and cold roughly the same?

And have you put a patent on your design as per the pic? ;)

@jamiehamy, yes, the potable water is fed from the cold supply after the stopcock, Dbl check valve, filter, PRV; the accumulator optionally plugs in at this point or expansion vessel if not.  The supply branches at this point to feed both the DCW and DHW as well a fill loop to CH or UFH, but that's another story. 

 

Track my companion thread since I seem to be running ahead of you.  A lot of this stuff has been covered in earlier threads, so search and browse :)

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Thanks! Will do. 

 

Got price back which has has taken me back slightly. It's not got a break down but is £8700 for First Fix,  which I'm assuming includes the Megaflow (£1500), manifolds with stop valves, pipes, running the supply into the house and preparing the soil pipes. 

 

Second fix is £3375 with us buying all taps, valves etc. 

 

We have-

 

Hot water  -

10mm x 7

15mm x 5

 

Cold water

10mm x 7

15mm x 8

 

Shower waste - 3

Bathwaste - 1

Sink waste -  7

Toilet waste -  4

Mhrv condensate waste -  1

 

Seems on the high side on first glance - any thoughts? I don't have any breakdown at this stage. 

 

Thanks,  J

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