Large workshop, very cold, mulling over what might work

[Ferdinand]

A couple of further thoughts.

 

You need to have designed your complete install method before you start, including machinery and number of people / skills. The attractiveness of tin cladding underneath the insulation is (in addition to catching fibres and looking nice) that you can order it in custom lengths which will exactly match your pitch length. The downside is that you will then be handling 6-7m x 0.8m hunks of corrugated 5m in the air, so it will be a sod to handle, even with something like a small spider crane or a 5m high board lifter.

 

I can see one scaffold tower plus a powered lift platform being an practical and cost-effective combination for a rapid install.

 

And the "how to attach to steel" still needs to be bottomed-out - I would suggest, once you have a method selected, a full scale trial on one small section of roof which is the left for a month to see if anything goes wrong.

 

I was attracted to things like sheep netting and mesh fence because they come on rolls just like rockwool, so you can install the holding layer with the insulation at one time, and the sections of roof you have already applied will support themselves as you move up (or down) the strip.

 

What about the use of PIR (or maybe sheet insulation of more robustness if necessary?) tacked up by expanding foam with a further "whoops" loop to catch any Great Collapsing Sheet of Celotex disasters as a layer to support and shield the rockwool?

 

Or a similar mechanical solution using say sheets EPS?

 

There are further benefits - it is light to handle, supplies extra insulation, can very possibly be used to cover your steel-rafter cold bridges.

 

If you use alu-faced celotex with the non-printed side facing down that may also help your lighting, and you can seal it with alu tape to give you a 99% moisture seal to the roof.

 

Just thoughts.

 

F

[Roger440]

7 hours ago, Ferdinand said:

A couple of further thoughts.

 

You need to have designed your complete install method before you start, including machinery and number of people / skills. The attractiveness of tin cladding underneath the insulation is (in addition to catching fibres and looking nice) that you can order it in custom lengths which will exactly match your pitch length. The downside is that you will then be handling 6-7m x 0.8m hunks of corrugated 5m in the air, so it will be a sod to handle, even with something like a small spider crane or a 5m high board lifter.

 

I can see one scaffold tower plus a powered lift platform being an practical and cost-effective combination for a rapid install.

 

And the "how to attach to steel" still needs to be bottomed-out - I would suggest, once you have a method selected, a full scale trial on one small section of roof which is the left for a month to see if anything goes wrong.

 

I was attracted to things like sheep netting and mesh fence because they come on rolls just like rockwool, so you can install the holding layer with the insulation at one time, and the sections of roof you have already applied will support themselves as you move up (or down) the strip.

 

What about the use of PIR (or maybe sheet insulation of more robustness if necessary?) tacked up by expanding foam with a further "whoops" loop to catch any Great Collapsing Sheet of Celotex disasters as a layer to support and shield the rockwool?

 

Or a similar mechanical solution using say sheets EPS?

 

There are further benefits - it is light to handle, supplies extra insulation, can very possibly be used to cover your steel-rafter cold bridges.

 

If you use alu-faced celotex with the non-printed side facing down that may also help your lighting, and you can seal it with alu tape to give you a 99% moisture seal to the roof.

 

Just thoughts.

 

F

 

Handling tin sheets that size, even with the gear carries some risk. Get hit by one, you may well not live. You say a scaoffold and a cherry picker, but you still have to get it up there. Ive handled 5 metre long sheets before on vertical cladding. That was a nightmare. And we still have to keep the rockwool in situ while the tin is fitted.

 

Your PIR suggestion is pretty much my suggestion last night. But without the rockwool.

 

If i was sticking up PIR, why bother with the rockwool? I priced up 100mm PIR for the whole job. Its wasnt as bad as i feared.

 

With your rockwool suggestions, do you envisage that being up against the existing roof, or with a gap/air space

 

 

Edited October 17, 2022 by Roger440

[Roger440]

20 hours ago, Nickfromwales said:

PIV  

 

Use the ugly spray foam and just look at the metal beasties vs looking up!?! 🙄

 

I know it makes sense at a practical level. Just not so much from a cost point of view.

 

Plus, ive got to get someone that wants to travel this far.

[Nickfromwales]

2 hours ago, Roger440 said:

 

I know it makes sense at a practical level. Just not so much from a cost point of view.

 

Plus, ive got to get someone that wants to travel this far.

Jumper it is, then  2 jumpers when it gets really cold  

[markocosic]

Go to America (via YouTube) for big cheap buildings.

 

 

You either spray foam these structures (cheap) OR you effectively build an insulated inner wall and hack ventilation holes into the walls / ridge such that the tin is just a ventilated rainscreen (expensive). With a hiding hole that's properly heated/cooled with an A2A unit for defrosting between jobs. 

 

 

IMO paint booths should be an internal space partitioned off from the rest so that you can keep the grinding/welding shite and pigeon shite away. Air feed your mask with fresh air rather than using a 3 foot fan to impart a texture finish of bugs and dirt onto the car. 😉

 

Heat that BEFORE the paint job and AFTER the paint has tacked frankly with fan heaters. Cars stay warm for some time. Don't leave the paint tins in there when doing this. Definitely don't leave the dinitrol tins in there whilst doing this. Worst mess ever. Except for that bloke whose cat ran into the garage, got blasted with waxoyl and knocked over the lamp whilst running back into the house with the beige carpets... (ex Land Rover and MX5 owner here...)

 

 

 

Between those Z-purlins you have 5 bays to span ~6 metres (plan view) or ~8 metres (roof diagonal) They are not so big.

 

You want some ventilation above the insulation to clear any moisture that does live there. You don't care for a flat ceiling.

 

Are roofing membranes fire retarding? Wrap one end around a piece of wood (a couple of times) and staple to the wood. Attach this wooden batten to the Z-purlin at one eave using self drilling tek screws that'll whizz through wood then self drill into the purlin. Repeat for other purlins keeping it taut. (perhaps Wrap over a round bar clamped to the purlin at the ridge with some small spacers (so that you can pull the thing tight) and another round bar clamped to the purlin at the opposite eave. Hang weights / pull tight. Tek screw it to every  purlin using battens to clamp it.) Insert 1200 mm batts of mineral wool on top of the membrane (with a couple of squirts of foam to hold hem to the membrane in case it tears for some reason and you avoid these falling on your head) between the purlins leaving a gap above to the roof. Repeat down the length of the building. Curse at the last 1200 mm?

 

Or do the same with chicken wire held up to the purlins with battens and mineral wool above. That'll never burn. Your steel will be ok if there's enough airflow in the air gap above. Blast it with white emulsion for lighting. Pop a piece of plasterboard down the ridgeline for lights. Pop two more strips at the eaves for lights?

 

[Roger440]

13 minutes ago, markocosic said:

Go to America (via YouTube) for big cheap buildings.

 

 

You either spray foam these structures (cheap) OR you effectively build an insulated inner wall and hack ventilation holes into the walls / ridge such that the tin is just a ventilated rainscreen (expensive). With a hiding hole that's properly heated/cooled with an A2A unit for defrosting between jobs. 

 

 

IMO paint booths should be an internal space partitioned off from the rest so that you can keep the grinding/welding shite and pigeon shite away. Air feed your mask with fresh air rather than using a 3 foot fan to impart a texture finish of bugs and dirt onto the car. 😉

 

Heat that BEFORE the paint job and AFTER the paint has tacked frankly with fan heaters. Cars stay warm for some time. Don't leave the paint tins in there when doing this. Definitely don't leave the dinitrol tins in there whilst doing this. Worst mess ever. Except for that bloke whose cat ran into the garage, got blasted with waxoyl and knocked over the lamp whilst running back into the house with the beige carpets... (ex Land Rover and MX5 owner here...)

 

 

 

Between those Z-purlins you have 5 bays to span ~6 metres (plan view) or ~8 metres (roof diagonal) They are not so big.

 

You want some ventilation above the insulation to clear any moisture that does live there. You don't care for a flat ceiling.

 

Are roofing membranes fire retarding? Wrap one end around a piece of wood (a couple of times) and staple to the wood. Attach this wooden batten to the Z-purlin at one eave using self drilling tek screws that'll whizz through wood then self drill into the purlin. Repeat for other purlins keeping it taut. (perhaps Wrap over a round bar clamped to the purlin at the ridge with some small spacers (so that you can pull the thing tight) and another round bar clamped to the purlin at the opposite eave. Hang weights / pull tight. Tek screw it to every  purlin using battens to clamp it.) Insert 1200 mm batts of mineral wool on top of the membrane (with a couple of squirts of foam to hold hem to the membrane in case it tears for some reason and you avoid these falling on your head) between the purlins leaving a gap above to the roof. Repeat down the length of the building. Curse at the last 1200 mm?

 

Or do the same with chicken wire held up to the purlins with battens and mineral wool above. That'll never burn. Your steel will be ok if there's enough airflow in the air gap above. Blast it with white emulsion for lighting. Pop a piece of plasterboard down the ridgeline for lights. Pop two more strips at the eaves for lights?

 

 

Thanks. Some good suggestions.

 

Spray foam does indeed seem cheap in the states. Though in the big building, they do only put an inch or 2 on. Foam here, for a decent thickness, say 120mm total, closed followed by open cell wont see change from £15k.

 

One question. I see what you are saying re string the menbrane across. But how do you then get the batts in ABOVE it?

 

Re the "spay booth", i always intended a seperate room. The fan will be via floor level ducting, effectively a cross draft arrangement. Not just a 3ft fan in the wall.

[Roger440]

50 minutes ago, Nickfromwales said:

Jumper it is, then  2 jumpers when it gets really cold  

 

Heated jumpers though!

[markocosic]

Batts from the side. Fit membrane in ~1 metre wide strips that it comes in. Post insulation in from the side. As you go along.

 

If you start from both ends and meet in the middle then you can probably arrange it, with mineral wool batts, such that there's half a metre of batt overhanging in each side before you put the final metre of membrane up underneath.

 

Is still be a little concerned about air pressure on windy days with a big door open sucking/pushing against this insulation though.

 

2" of spray foam is probably enough. U value 9,000 down to U value 0.5 and perfect airtightness.

 

£15k for materials and a month of misery saved seems good value to me. £300/month over 5 years even if borrowed?

[Ferdinand]

13 hours ago, Roger440 said:

 

I know it makes sense at a practical level. Just not so much from a cost point of view.

 

Plus, ive got to get someone that wants to travel this far.

 

If using spray foam, you could spray paint it afterwards to make it less obvious.

[Ferdinand]

13 hours ago, Roger440 said:

With your rockwool suggestions, do you envisage that being up against the existing roof, or with a gap/air space

 

I think that's the only one that needs a comment.

 

Yes - an air gap above.

 

I would install 2-4" less than the depth of the beams, and install it near the bottom.

[markocosic]

Weight of insulation may also be an issue - how much can these structures take?

[SteamyTea]

1 hour ago, Ferdinand said:

15 hours ago, Roger440 said:

With your rockwool suggestions, do you envisage that being up against the existing roof, or with a gap/air space

 

I think that's the only one that needs a comment

Can't you get wool insulation that fully fills cavities.

Think @joe90 used it.

He had a wet wall until he sealed it, seems not to have had adverse effects.

Still think that using cheap weed control membrane with mineral wool above it will solve the problems, and easy to fix.

may need to glue so battens, for easy stapling, to the steel, that is easy to do though.

[joe90]

2 hours ago, SteamyTea said:

Can't you get wool insulation that fully fills cavities.

Think @joe90 used it.

Yes I did, rockwall batts have a BBA certificate for full fill and I can say most definitely it does not wick moisture.

[Roger440]

On 18/10/2022 at 08:22, markocosic said:

Batts from the side. Fit membrane in ~1 metre wide strips that it comes in. Post insulation in from the side. As you go along.

 

If you start from both ends and meet in the middle then you can probably arrange it, with mineral wool batts, such that there's half a metre of batt overhanging in each side before you put the final metre of membrane up underneath.

 

Is still be a little concerned about air pressure on windy days with a big door open sucking/pushing against this insulation though.

 

2" of spray foam is probably enough. U value 9,000 down to U value 0.5 and perfect airtightness.

 

£15k for materials and a month of misery saved seems good value to me. £300/month over 5 years even if borrowed?

 

Good point about the wind! Didnt think of that.

[Roger440]

On 18/10/2022 at 10:03, SteamyTea said:

Can't you get wool insulation that fully fills cavities.

Think @joe90 used it.

He had a wet wall until he sealed it, seems not to have had adverse effects.

Still think that using cheap weed control membrane with mineral wool above it will solve the problems, and easy to fix.

may need to glue so battens, for easy stapling, to the steel, that is easy to do though.

 

Crazy thing is, wool is soooo much more expensive. 

 

Meanwhile, last year, farmers were burning fleeces becuase they were worthless.

 

I even looked at what was involved in taking raw fleeces and turning them into something useable myself. It just doesnt make sense at any level. Such is the mad world we live in!

[SteamyTea]

2 minutes ago, Roger440 said:

Crazy thing is, wool is soooo much more expensive. 

I should have clarified, mineral wool.

Using animal wool is just bonkers.

Edited October 20, 2022 by SteamyTea

[Roger440]

On 18/10/2022 at 08:42, markocosic said:

Weight of insulation may also be an issue - how much can these structures take?

 

Talking to my tame  steel building erector, its normally a non issue. Frames are normally much the same even if they are putting on a 120mm composte panel.

 

One would hope a competent spray foam installer would take account of that.

[Roger440]

Just now, SteamyTea said:

I should have clarified, mineral wool.

Using animal wool is just bonkers.

 

Ok!

 

Bonkers cost, yes. But enviromentally, it would be much better.

[SteamyTea]

5 minutes ago, Roger440 said:

But enviromentally, it would be much better.

Not really.  It may have a slightly lower embodied energy and CO₂ but sheep do a huge amount of environmental damage.  Not as if they are natural animals anymore.  They are specially bred and farmed intensely.

 

Edited October 20, 2022 by SteamyTea

[Roger440]

Ok, so i have finally gotr up into the roof space to have a better look.

 

A good point raised earlier, was if doing with some sort of membrane/rockwall about wind pressure above.

 

Looking at these pics, id guess it could by blocked off. But it would still need ventilation somehow.

 

As you can see in the third pic, a fair number of the screw holes leak slightly so get damp patches at times. I guess sealing these up will work, but thats a mamoth undertaking!

 

In the back of my mind i keep thinking, maybe just spend the money and replace the roof with composite steel. All problems fixed in one go. And white on the inside too.............. But VERY spendy.

 

Choices, choices. 

[Roger440]

As an aside, the cavity wall could be filled with EPS bead. But most of the electric cabling is in the cavity. How real is the issue with cable embrittlement?

[Roger440]

Ok, im back. Again

 

After lots of thinking, researching, pricing up etc, i think ive concluded that my cheapest viable and worthwhile option is celotex or similar in the roof, rockwool slabs on the walls covered in steel cladding.

 

Ill put the celotex in between the galvanised purlins, which means smaller pieces thus easier to fit, but will need careful detailing. This leaves airflow over. I intend to use 120mm which means that i can have 20mm covering the bottom of the purlins.

 

The only issue i see with that otherwise clever plan is the steel joists (red oxide) will be inside the thermal envelope in the roof, but outside it on the verticals, where they are in the cavity. 

 

Realistically, thermal issues aside, does anyone see a problem with that?

 

 

 

 

[Pocster]

Surely this would warm you up ?

 

 

[Roger440]

11 hours ago, pocster said:

Surely this would warm you up ?

 

 

 

Unlikely to be effective for extended periods. Maybe when i was younger............ 

[SteamyTea]

1 hour ago, Roger440 said:

 

Unlikely to be effective for extended periods. Maybe when i was younger............ 

I so wanted to mention something rude and totally inappropriate.