New workshop for 2020

[DBT85]

If you've sockets on every wall and are putting trunking up high and having drops then you can just do one 32a ring in 2.5mm because it goes around the entire inside. If you can't join both ends up for some reason then yeah 4mm radials in opposite directions from the CU works. Less of a pain than running 2 2.5mm in conduit and boxes for an out and back again journey.

I think I'd go with the 32a ring though. But then I'm fairly sure I can just go up from my CU, head left and keep going till I'm back at the CU.

TLC want £39 for 100m of 2.5 and £63 for 4mm. So theres small saving. No idea if it's a saving lost on having to then have another circuit mind!

Not sure I'd bother with 2 rings, though with surface mount it's easy to add later. You've got to be going some to use 7kw at once in a one man shop even with heat. Mine will most likely be a 32a ring, a lighting, maybe a 16a, maybe floor separate and then maybe separate for heat. No idea yet tbh!

Are you putting in anything in the floor or a 16a outlet just in case? Looking at some extractors on axeminster I was surprised to see so many with 16a plugs when the machine is only say 2kw. One was o ly 1.1kw. Maybe I've missed something.

 

[Sheptonphil]

Are you putting in anything in the floor or a 16a outlet just in case? Looking at some extractors on axeminster I was surprised to see so many with 16a plugs when the machine is only say 2kw. One was o ly 1.1kw. Maybe I've missed something.

Yes, two floor sockets and a 16A circuit. I use a floor socket to power the outlets on my island work bench to save having leads from wall to workbench. My Jet chip extractor used to trip the MCB in my last workshop on start-up if anything else was running till I upped the breaker to a C class one. It was a long way from the house and at the limit of the supply cable.

As I'm going in conduit I've a route around the room anyways so will probably go with the single core cables in 2.5 ring. couldn't see why so many are advocating radial.

 

[DBT85]

Ive seen plenty of rings that are out and back again in the same run of trunking or whatever. So that's why. A radial is the sensible choice there.

You also have the benefit of a radial being really easy to fault find. On a ring you could have a problem and not notice and end up cooking a cable because you're sucking 30a from one run of 2.5mm. I mean, it doesn't happen often but it can.

 

[flying haggis]

you can do 20A radials with 2.5mm

 

[MikeG.]

I'm honestly not clear why this is even a question. A small workshop, under 30 sq m........... What is the argument for diverting from the standard and all-but universal ring main? There is no great power demand, no great complication, easy accessibility of wiring. I don't understand what benefit there can be with doing something different.

 

[DBT85]

Well if one is unsure you ask a question. Often better and more pleasant than doing it and someone coming along and telling you you did it wrong or made a dumb choice.

There will no doubt be people that would suggest using radials over rings.

 

[MikeG.]

Just to be clear, I'm asking out of ignorance, rather than out of any certainty that a ring main is the right answer.

 

[DBT85]

Not sure there is a right answer Mike. All depends on the layout and stuff I suppose. If the CU is in the middle of the wall and you only wanted sockets on that wall for some daft reason, then radials make way more sense than rings.

In this setting where you're going to bang up way more sockets than a normal room and on every wall you can, a ring just seems to be sensible.

The other question really is do you put up one ring all the way round and then do JB on that ring with 2.5mm drops as spurs for each socket, rather than going up and down for every drop which is a bunch more cable and a little more work. Alternativly I think (and I may be wrong) that you can do 4mm spurs and have more than one socket on it.

In theory you could plug in 2 appliances to a socket that try to suck 26A but from what I can gather the socket will die before the 2.5mm cable will in such a situation as they are only rated to 20A anyway.

Someone who does the lectrics needs to weigh in.

 

[Sheptonphil]

Well, another productive day.

Finished all the internal OSB, and external membrane and counter battens. Not sure why I’ve got seven packs of insulation left over, I expected a couple, but never mind, it’ll go in between rafters now. The shell to a great extent is finished. I had sufficient membrane spare to cover the acoustic insulation on the house side, not because it needed it, but more to keep rain off it till the roof is on.

Kinda building up the courage to start the roof on my own, it was going to be a two man job with pre-made trusses, this changed to a two man job cut vaulted roof, and now either wait until restrictions are lifted so I can get the help in, or just crack on with it alone.

Meanwhile, after talking to my electrician I can at least start routing services to the workshop. He is basing circuits on a 32A ring main, separate 16A socket, lighting and a wall curtain heater or two. He said to put 40mm trunk around ceiling perimeter and conduit drops from that. There will be seven 600x600 led panels plus task lighting, six in the main workshop, one in the plant room where the extractor and compressor will live. There will also be a small sink in there, and probably a kettle. Fortunately I have drainage right outside the rear of the plant room. Garden sockets and lights will be powered from the workshop consumer unit as well. I’ve got a dual RCD six way consumer unit, but that stuff is above my pay grade.

I drove a 1.2m earth rod in at the workshop end ready for hooking earth up. Wall has been drilled from the office to run a couple of Ethernet cables, which fortunately came out near the point the SWA cable is gong to start its journey.

Need to add a new cupboard by the meter cupboard to put a 100A Fused isolator. From the meter cupboard, a service block in the meter cupboard will split the supply to both house consumer unit and workshop isolator, then on to the workshop in SWA. Fortunately there is a service provider switch in the meter cupboard to kill the power when my sparky comes to split the load so no need to pull the main fuse.

There will be two conduits run in a trench with draw cables in case I’ve missed something in the future, and will pick up the blue water pipe halfway to the workshop.

Cutting out the wall to accommodate the new service box raised a few eyebrows when the missus came out to see what the grinding and hammering was about, to find a gaping hole in the wall and a pile of rubble.

That job is to be continued tomorrow.

 

[flying haggis]

if you are putting another meter box in next to the existing one, check that the original one might have a lintel above it so the new box might need one too

 

[Sheptonphil]

That is the extent of the hole already made, it's a mini version of the meter box. I have a 140mm x 500mm steel plate to bridge over the box.

 

[Sheptonphil]

Services now dug in from the house to workshop, could only go to 14” as hit bedrock. I’ve put tape six inches above as a warning, but there’s no way I’m digging 25 metres of bedrock up.

The turf went back down great afterwards, so should soon be back or square one.

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[Sheptonphil]

Rained off Thursday and Friday and not allowed to do noisy work over the weekends, management doesn’t want me to annoy neighbours, but it turned fine today so got on with the ceiling.

Managed to get hold of twenty off 14-17 feet lengths of 7x2 reclaimed ceiling joists (Two were 8x2) for £100. Had 200-300 nails to remove, but well worth it. This is some seriously good wood, straight grained, hard as hell, no knots. I’m putting in a flat ceiling. I’m having a fairly shallow pitch roof at 22.5degrees and the amount of space to just store more cr@p that ‘will come in handy one day’ wasn’t worth preserving. I shall insulate and plaster board the ceiling then install six 600mm led panels. I’ll put an access panel in for future use for access to services though.

Trimmers to go in tomorrow to fill between first joist which is at 600mm and end wall in same orientation rafters will go, else the rafters wouldn’t have cleared the first joist. Not sure if I need noggins as well, but I’ve got the off cuts of the joists left over, so may as well add them in. All joists were fixed with 70mm heavy duty angle brackets with 45mm Tec screws on diagonally opposing sides and toe nailed other side. The walls were 6-8mm out of plumb before, but they were pulled in line and secured plumb. They’re going nowhere now.

I’ll put my P5 22mm boards on the ceiling temporarily to use as a platform when building the cut roof. I managed a Wickes delivery for this week.

 

[DBT85]

Looking like good progress despite everything!

Those evolution sliding saws do a good shift despite the cost. I think mine was £65 refurbished from evolution directly on ebay!

 

[Sheptonphil]

Looking like good progress despite everything!

Those evolution sliding saws do a good shift despite the cost. I think mine was £65 refurbished from evolution directly on ebay!

The saw is decent enough for this type of work for sure. The evolution ‘cut everything with one blade’ blade, cuts nothing nicely, kinda hacks it off, so I use a Saxton 80 tooth tct blade and get a perfect cut. It’s done all the framework, the joists and will see the rafters through for sure.

It’s starting to feel more like a building now

 

[Sheptonphil]

The whole week was a washout here in the South West. Finally managed to make my ridge beam and purlin supports on Friday.

Saturday the support posts were installed along with the ridge beam and a couple of rafters clamped on to check alignment and position of the purlins posts. Being a noise free zone weekends (SWMBO), construction is limited so have to wait till Monday to fit the purlins across and start to mark the seat cuts for the rafters.

Looking like a fine week ahead, so hopefully the roof construction can be finished ready for slating.

 

[Sheptonphil]

A little more slow progress today

These lumps of timber are hard work on your own, 5m lengths of 7x2 are a fair weight. The 8x3 purlins even more so.

Still, both purlins raised and installed, alignment between ridge and wall plate confirmed with string.

The first four rafters are now cut in, three cuts, for ridge, purlin and wall plate, not sure if they’re crows feet or bird mouth, but I do know the rafter is seated nicely on all the contact points.

I’ve used a steel plate to join the rafters over the ridge beam and secured them at the the purlin and wall plate with brackets.

Wet tomorrow, but come Wednesday I hope to finish the last eighteen rafters. The first ones I made fitted snug along the length of the ridge in all three places, so I can use it as a pattern to cut the others one at a time, and check each as I go.

 

[DBT85]

How did you find the long lengths for twist and stuff? All nicely straight?

Always a bit of a guessing game unless you are able to pick it yourself.

Also, is that a rather large step to get into the door?

 

[Sheptonphil]

I struck lucky with the roofing timbers. It was a single lorry order from a timber yard in Birmingham the day before they closed for covid. I had ordered all C16 graded, but they supplied C24 at the same money. Every length is straight, no crowning at all, and no twist. I used string between wall plate and ridge in case there was an unseen bow in a rafter, and didn’t want to set the purlin to a bent piece of wood. The rafters just touch all three edges when rested on them .

The doorway bottoms are yet to be cut away. There are two pieces of 4x2 at present which will be removed in all three doorways, I’ll cut them out when I’ve put the roof on and stopped banging things around. At least there is no chance of anything becoming mis-aligned this way.

The step in will end up being about a brick and three quarters outside and one brick inside by the time the threshold is fitted. I’m putting a custom made stable door on the front with a large fixed window in the top half.

 

[Sheptonphil]

Outer gable finished, all stud work and membrane fitted with the battens ready to take cladding. Middle batten to fix yet, couldn’t reach it over the gable top so will do when the fence is down to do cladding.

Couple more rafters cut, hopefully the rest tomorrow.