Another workshop insulation question

[JonParticipant @jon]

Your looking at a linear 49 sq/m will be a lot more in reality.

Biggest problem with mine is concrete floor where the cold travels up your bones. Best cure lasts about 3 yrs the cheap 3mm rubbed rubber matting.

Mine has apex roof exposed to the roof. At first i just boarded underside up with 3/16" plywood, massive benefit. Years later decided on chipboard interlocking on top of the rafters together with 4" rockwool in fill = little gain just worth while.

Best bang for buck is the interlocking chipboards think 2.44m tall x 605mm, easy and quick to install on to battens. Mine has no infill just air space so its not a direct transfer of cold and what counts, battens might have been 3 x 1 1/2"?
Would need 33 boards (linear) at £11 each + min 52 battons £2.3 ea + screws etc all in approx £500 plus roof.
Beauty is you can make up and or bolt racking and shelving to it = no lost space and it keeps the noise down substantially.

If use cellotex or similar you have nothing more than a pin board for £612 min unless its covered over.

Even with all that having been through it your biggest source of cold will be from them garage doors and the gaps.
I did at one point Cellotex 2" over the door, made virtually no impact so installed a painting sheet across the width, that cured it temporary. Then i partitioned it off with that chipboard that cured it, really really cold the other side with cellotex lined door, 5 mins your out of there.
All i have now is a puny 1kw oil filled rad only ever left on lowest setting and on thermostat, takes 1 1/2hrs to warm in the coldest of winter. To speed up i do use a calor gas heater from 7.30am ish.

5M X 5M is a fairly large space to warm up quick or even keep it relatively warm enough to work in. Dependant upon what you need i would think about partitioning off which could double the wall space.

By the way tools never oiled and coolant used daily.

[BazyleParticipant @bazyle]

I can't change my original post but several people have posted corrections so the newer values are available to readers. I got my figures a decade ago and was remiss in not keeping up with changes. Closed cell EPS used to be rated better than open cell PUR and both way better than the very open fibreglass structure due to convection contributions.

[Dave HalfordParticipant @davehalford22513]

I did at one point Cellotex 2" over the door, made virtually no impact so installed a painting sheet across the width, that cured it temporary. Then i partitioned it off with that chipboard that cured it, really really cold the other side with cellotex lined door, 5 mins your out of there.

This sound very like a draft issue Jon.

[Roderick JenkinsParticipant @roderickjenkins93242]

OK. I've done some sums. Celotex/Kingspan is certainly the way forward. Concrete block / 50mm Kingspan / 11mm OSB gives me a U of 0.4 which is poor compared with a new build wall requirement of 0.16 but not too bad compared to a refurbishment which the regs seem to allow to be 0.3 to 0.55 (if I understand it correctly).

I've bought a pallet (25 sheets) of 50mm Kingspan seconds from these people **LINK** for £432 delivered which should do the job. I'll keep you posted.

Rod

[JasonBModerator @jasonb]

Rod if using seconds and relying on the foil for your vapour barrier then buy an extra roll of ali tape so any small holes can be sealed and not just the joints. If you also want to calculate where the "dew point" is within that construction you will find it's in the insulation so any moist air getting to that point will condensate out within the insulation so best to seal so that can't happen.

[Howard LewisParticipant @howardlewis46836]

My shop is small, 3 x 2 m internally. three walls and the roof are insulated with 50mm glassfibre, the wall with the fire door with 6 lever lock has 100mm, because of the weight of the door called for heavier timber to support it. The sloping roof is now covered with a one piece EPDM rubber membrane.

The floor is 3/4 (or the metric equivalent) ply, on 8 x 2 bearers; on top of this, in the central walking area, are rigid, openwork, plastic mats. The back wall is close to a high fence, and the far end is partially sheltered by a bay tree.

The door end is barely two metres from the back of the house.

When cold, (East Anglia).a thermostatically controlled 2Kw fan heater runs for about 10% of the time. When the ambient temperature dips to 5'C or less, a 60W tubular heater under a bench is switched on and this keeps the temperature just high enough to prevent rust problems, (Being a steel bench – well cluttered, this slightly helps to radiate the heat).

I feel that ventilation is important, to get rid of the water vapour that we exude in our breath and perspiration. Any form of combustion heater is a No No in my view for this reason.

Ventilation is provided by two small fixed vents in the back wall, and a 6 inch fan high on the back wall, with intake through a weatherproof cowl. Unless it is raining, or it is cold, I often work with the door open, so the fan does not see a lot of use. Rust problems are almost non existent.

Howard

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by JasonB on 21/09/2018 07:05:09:

Rod if using seconds and relying on the foil for your vapour barrier then buy an extra roll of ali tape so any small holes can be sealed and not just the joints. If you also want to calculate where the "dew point" is within that construction you will find it's in the insulation so any moist air getting to that point will condensate out within the insulation so best to seal so that can't happen.

Jason, thanks, I hadn't considered that. And thank you everybody else for your experiences. It all helps balance the cost/effort/effectiveness equation in this benign ( if possibly slightly salty) climate down here on the south coast.

Cheers,

Rod

[Ron LadenParticipant @ronladen17547]

Posted by Roderick Jenkins on 20/09/2018 22:03:35:

OK. I've done some sums. Celotex/Kingspan is certainly the way forward. Concrete block / 50mm Kingspan / 11mm OSB gives me a U of 0.4 which is poor compared with a new build wall requirement of 0.16 but not too bad compared to a refurbishment which the regs seem to allow to be 0.3 to 0.55 (if I understand it correctly).

I've bought a pallet (25 sheets) of 50mm Kingspan seconds from these people **LINK** for £432 delivered which should do the job. I'll keep you posted.

Rod

Rod, just a thought but I prefer WBP ply over OSB sheet as it gives you a smooth surface, you can get OSB with a smooth side but it is more expensive. I dont think the cost difference between WBP and standard OSB is that much.

Ron

[JasonBModerator @jasonb]

Don't pin (clip)your cables on the surface run them in conduit and/or trunking for physical protection down to metclad boxes. Workshops fall under part P so you won't get it signed off unless it is protected and it is just good practice due to the risk of things getting knocked. Also makes it relatively easy if you want to add more drops.

On the subject of metclad, MK do double socket outlets with the rocker switches at the ends rather than between the sockets which makes it easier to use if you have gloves on or are just blessed with fat fingers.

[JourneymanParticipant @journeyman]

Posted by The Oily Rag on 21/09/2018 10:38:35:

I had thought of running the ring main in the air gap/vapour barrier and pulling the cables through the insulation and through a fixed mounting board across frame members on which the relevant electrical items are mounted.

Definitely don't hide cables in the wall. Any future changes or additions will become more difficult. Go with Jason's surface mounted conduit, better still use surface mounted trunking for all the cables and sockets. Such as this from *** TLC *** very neat. All the wiring can be concealed and the only extra cabling is for the lighting circuit.

John

[MeunierParticipant @meunier]

A timely thread for me, having just moved house and setting up the workshop again in a sub-basement.
The external wall is concrete block lined with 20mm EPS and faced with 10mm plasterboard which obviously won't be much good for hanging shelves and tooling, etc, on. Will need to panel it with something more substantial.
Looking on Castorama website, equivalent to B&Q, it looks like a choice between
MDF 25mm / Green MDF 18mm / Green chipboard 28mm / OSB 22mm or Hardwood Ply 18mm.
All except the OSB have a smooth/faced finish. What would seem to be the best choice ?
TIA
DaveD

[Roderick JenkinsParticipant @roderickjenkins93242]

Does anybody have any experience of this stuff ? Seems like a U bargain. My bargain pallet of Kingspan is likely to be a bit scrappy so an extra vapour barrier could be useful.

Cheers,

Rod

[JasonBModerator @jasonb]

OTT as just a vapour barrier to compensate for damaged foil face, polythene would do for that.

If you want to use it's additional thermal properties then to get the best out of it it then you should not squash it up so really needs to be battened and counter battened. One I prepared earlier before, during and after

[Martin 100Participant @martin100]

Except anyone with any sense would plan their workshop size, location with respect to boundaries, location to the main property and the method of construction to ensure 'planning' and 'building regulations' did not apply. Then there would be absolutely no fee to pay for anything.

The an earth has to be exported along the SWA cable from the head end, it will almost always be the PME earth connected to the armouring to ensure suitable fault protection and fault clearance times for the cable. The cable merely has to be installed to prevent any damage. Burying is not always required, but if it is then burying has to provide some warning to anyone coming along, commencing a dig and encountering the conductor 'hidden' just below the surface. The cable depth of burying is only specified for the main incoming feed into a property and network operator feeds in the carriageway and pavement. Anything on your own property with a sub main or individual circuit is not prescriptive as to cable depth. There are recommendations but that is all they are.

In addition this 'exported' earth then has to be totally isolated at the outbuilding and a local earth provided unless you have means of adequately ensuring against rise of earth potential from a fault or lost neutral which is what the equipotential bonding is there for in the main property.

Cabling with a flexible extension cable can easily lead to a situation where a fault occurs and is not cleared in time, leading to a fire hazard and a shock hazard when metalwork within the outbuilding installation rises above the potential of the local earth. Just plonking an RCD in the installation at random locations may not be enough.

It might all be viewed as just 'part p' and denigrated in some / many eyes but in reality an outbuilding electrical installation requires a common sense properly engineered electrical installation that in the case of a new installation meets the requirements of BS7671 or if you want to be pedantic the equivalent IEC requirements.

Fail to comply either as a 'pro' or an amateur and it results in injury and you will almost certainly be prosecuted even if you have subsequently moved house.

But your biggest problem was wanting to build something that requires Planning and Building Regs. 15m^2 timber or or 30m^2 brick / block / stone should be enough for most 'home' workshops. If you live in a national park or other location protected from development then you have some sympathy.

Forgot to add you can get an electrical installation in a structure outside the remit of building regulations (separation / use etc)   'certified' by an appropriate person / organisation without any building regulations application being made. 

https://electrical.theiet.org/wiring-matters/issues/51/part-p-third-party-certification/

Edited By Martin 100 on 08/10/2018 14:10:00

[SamsarandaParticipant @samsaranda]

Ian, what part of the country do you reside in? It would seem that your planning and building control departments are over zealous to extreme. I live in East Sussex and our building control has apparently been privatised with a company located in Tunbridge Wells being the contractor concerned, I might add that I live some distance from them just outside Eastbourne, fortunately do not need any services from them and if your experience is anything to go by I hope I don’t. It is hardly surprising that people tend to steer clear of official certification, it is counter productive for a safer environment.

Dave W

[JC54Participant @jc54]

If you think that running electrics to the shed is ludicrous try getting the go ahead to lower a path so that you can drive onto your property and not block the road with your legally parked vehicle.. LOCAL COUNCILS..

[Neil WyattModerator @neilwyatt]

Posted by John Collingwood on 08/10/2018 20:34:01:

If you think that running electrics to the shed is ludicrous try getting the go ahead to lower a path so that you can drive onto your property and not block the road with your legally parked vehicle.. LOCAL COUNCILS..

Once I saw a figure for the impact that all the people who had dropped kerbs and put hard surfaces on their front gardens in Birmingham had caused in terms of flash flooding before planning controls were brought in.

It's not just little positive actions that can add up to make a difference!

Neil

[Martin 100Participant @martin100]

Ian, as mentioned above about third party certification, the electrical installation can be officially self certified by an electrician registered under any one of numerous official 'independent' bodies For instance NICEIC or NAPIT or Elecsa or Stroma (plus others too) The actual cost to the installer is so insignificant (about a fiver) it is totally lost in the labour and materials and rarely even becomes a chargeable item.

The conductor size proposed might appear 'over the top' but it might be proposed for extremely valid reasons. No one would deliberately use oversize cables as they are a pain to install.

One thing is clear, with a building where the construction of the structure is outside the remit of building control There is absolutely no need to pay ANYTHING to building control nor indeed for them to be involved at all. Plus I doubt there is now a building control department anywhere in the UK with any valid expertise on electrical installations.

You appear to prefer to circumvent the requirements for a fixed installation by using an extension cord. A 'new ' installation must legally meet the basic safety requirements, they are a couple of paragraphs specified in part P and are met by complying with BS7671 or by an equivalent IEC standard. That requirement is usually ensured (in the case of those not appropriately skilled) by employing someone competent and who can self certify, not by employing someone to install and then paying hundreds of pounds to building control (only for them to employ a subcontractor)

For those appropriately skilled and qualified that deem part P certification an insult we, as ever design, install and test our own installation to fully meet the requirements (and some of us would if necessary be prepared to argue our case in court)

Your extension cable is not and never will be a safe substitute for a properly designed and earthed outbuilding installation. It could, regardless of your specially installed outdoor sockets, kill you or someone else. That situation may arise as a result of issues occurring outside the boundaries of your property and totally within the remit of your distribution network operator, and while your installation within the house will, if properly installed remain safe at all times, your extension to the outbuilding and particularly exposed metalwork on any machinery will not.

As dirty harry, the well known electrician allegedly once said, do you feel lucky?

[FMESParticipant @fmes]

Posted by The Oily Rag on 09/10/2018 09:29:21:

'All house earths were now bonded to the incoming neutral and hence at my protestations admitted that they now run just a two wire system and a dead short would always exist between earth and neutral.'

A few years ago while having a new digital meter fitted, the engineer was explaining ( or trying to) that the Neutral is effectively the 'Company Earth' and that the House earth was belt and braces with any potential difference being between the Live and Neutral / earth.

What you are saying here seems to corroborate that statement.

[MuzzerParticipant @muzzer]

Posted by The Oily Rag on 09/10/2018 09:29:21:

At my comments about the uselessness of IEE488 regulations then they just shrugged their shoulders, suck it up its cheaper for us to distribute this way.

Ah, sounds as if they installed a GPIB cable instead of a mains supply. That would explain the fire. Was it ever described as IEE488??

If the neutral and ground were NOT connected together, I'd be very worried. The neutral would be able to float anywhere between ground and 240Vac which wouldn't be fun. Whether the neutral is connected to ground back at the substation or at the premises shouldn't matter a damn. Various schemes are allowed.

Murray

Edited By Muzzer on 09/10/2018 18:44:16

[Roderick JenkinsParticipant @roderickjenkins93242]

Here's my pallet of Kingspan, nominally 50mm. A few are 40mm, which have gone on the party wall and there was one at 60 which has gone on the ceiling.

It's been quite awkward moving around the kit but the weather has been benign so most of the cutting has been done outside.

Two walls and the ceiling finished so far, with much help from my glamorous assistant ( Mrs J)

The softwood ply came from my neighbourhood bargain DIY store at 12.95 a sheet – Fairly crappy and It feels a bit damp but I guess it will dry if I keep the doors open. They delivered 20 sheets for £5. The Kingspan has been fitted between 50mm square battens screwed to the wall and fitted between the ceiling rafters (or are they joists?).

Cheers,

Rod

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