Workshop Build

woodturner

Hey guys. I post quite often on the forum and was looking for some advice from those of you who have more experience than myself. Some of you know I dabble a little with woodturning but I'd like to get back to fine furniture making. The 'shed' I am in at the moment is quite damp and cold. We may be moving to a new (to us) house which doesn't have any kind of workshop.
The first thing I'd like to do when we move is to build a proper dry and insulated shop. Question is though, would a block built shed be better than a steel clad insulated one? We all know the effects condensation has on cast iron tools and machine surfaces. I just wondered if either was better than the other? Build cost doesn't matter.

magicbastarder

i'm going to follow this one with interest; i've recently wired up a 13' x 6.5' shed (block, concrete floor, flat roof) and the main issue i've had so far is the cold construction flat roof; once or twice over christmas, it was weeping with condensation. i've not done anything with regard to insulation yet.

woodturner

I wasn't in my workshop much over the Christmas but when I went back into it a couple of days after the holidays there was light rust on the bed of the lathe. This was even with an old heavy blanket thrown over it. For my tablesaw I lowered the blade and cut a piece of 4 mm ply to cover the whole table. That prevented rust from forming on the table. I keep my handplanes and other hand tools inside but if they had been in the shed they would have been covered with rust.
When I do get building a workshop I will insulate it pretty well and get some sort of heating into it. I've read that that helps prevent condensation

woodturner

magicbastarder wrote: »

i'm going to follow this one with interest; i've recently wired up a 13' x 6.5' shed (block, concrete floor, flat roof) and the main issue i've had so far is the cold construction flat roof; once or twice over christmas, it was weeping with condensation. i've not done anything with regard to insulation yet.

What did you roof it with?

Calahonda52

I would think a block build, with A roof is better, suitably insulated.

Just on the condensation issue, you know the science already but for those who don't lets dabble a bit.

At normal room temperature, say 20 degrees C, air contains a certain amount of water in the form of water vapour.

A main source of this air in a house or workshop is human breath, especially in bedrooms at night..

At the same temp, if the amount of water in the air becomes too much, e.g. in a bathroom with no ventilation, it reaches saturation point and condenses out on colder surfaces such as windows and toilet cisterns and the like.

The colder the air, the less water it can hold so condensation becomes a bigger issue.

The temp at which it condenses out is called the dew point (DP)

The other factor isn this is relative humidity RH and the relationship between air temp, RH and DP can be seen here dpcalc dot org

Typically RH in Ireland is pretty high so dew points of 16 degrees are not uncommon: 12 and 14 are common

[ Post 7 in thread number 2055848417 explains it pretty well.]

What this all means is that if you heat the workshop and are working in it, the moisture content will go up and then when you leave it cools down.

It take s a lot of heat to heat up an old Wadkin cast iron tool, so its nearly always the fall quy for the damp.

Heating is particularly an issue if you have no recirculation dust extraction.

When I was working the Wadkin tools with my late father in the 60's in his workshop we left the doors open.

At night the tools were covered with sacks and then plastic and when it was really cold he stuck a light bulb under the machines.

The bottom line is to insulate as well as possible and keep the tools as warm as possible on a permanent basis.

A good dehumidifier will also help as ids apparent from the above discussion, the Rolls royce version being one that fires once the RH reaches a certain level.

woodturner

Thanks for your post Calahonda. The woodwork forum is quiet at times and I hope more will chime in with their experiences

magicbastarder

woodturner wrote: »

What did you roof it with?

3/4" WBP with two layers of torch-on. it's single glazed too.
regarding dehumidifiers, i was running one (a small cheap one) in it over the christmas period, and it frequently froze up, so that wasn't much use.

gutteruu

Calahonda52 wrote: »

I would think a block build, with A roof is better, suitably insulated.

Just on the condensation issue, you know the science already but for those who don't lets dabble a bit.

Bit of a mad suggestion, but a few weeks ago on the radio they were suggesting to put a sock with cat litter in your car to stop windows fogging up. Well as mad as its sounds it 100% works. (Honestly, try it)

So 1 sock in a big estate car for over a month soaks up enough moisture to stop condensation. Surely by this logic throwing a 5 quid bag of cat litter in the corner of your shed would soak up enough moisture to help prevent condensation for a few months of the winter? I think cat litter is fullers earth but something with more silica would probably work better.

magicbastarder

dunno if they still have them, but a few months back, dealz had dehumidifier kits (silica based, i guess) for €1.49 each.

Calahonda52

Was in a marine gaff today, saw low wattage 240 volt tube heaters that are used on small craft engine rooms over the winter, very safe looking, come with clips for fixing on wall etc

BenAtar

magicbastarder: i'm going to follow this one with interest; i've recently wired up a 13' x 6.5' shed (block, concrete floor, flat roof) and the main issue i've had so far is the cold construction flat roof; once or twice over christmas, it was weeping with condensation. i've not done anything with regard to insulation yet.

This condensation issue resonates with me - I have exactly the same issue magicbastarder.
My shed is 20' x 20' block, concrete floor, flat felt roof. Internal dividing wall, so two rooms of 20 x 10'. One room suffers from bad dripping condensation in freezing weather conditions...it has no insulation on the ceiling at all. The other room is ok, no dripping condensation...it has ceiling insulation. The contrast between the two rooms is stark. The insulated room is my workshop, the other room is used for storing paints, etc, etc.

woodturner

Well I've gotten a quote for a steel clad shed, insulated roof and wall cladding, insulated small steel door and insulated roller door. 10' high walls 30' x 20 ' supply and erect for 13,500. That does not include the base which I'll have to sort myself. I reckon I'd build a proper block shed with tiled roof for less than that.

magicbastarder

BenAtar wrote: »

it has ceiling insulation.

how is it insulated? one of the issues i would have would be not trapping moisture in there if i was to insulate it...

BenAtar

magicbastarder wrote: »

how is it insulated? one of the issues i would have would be not trapping moisture in there if i was to insulate it...

Bog standard glass fibre attic insulation over blockboard sheeting. I'm told that plasterboard absorbs / retains moisture, so should be avoided. Hence the blockboard.

Calahonda52

woodturner wrote: »

Well I've gotten a quote for a steel clad shed, insulated roof and wall cladding, insulated small steel door and insulated roller door. 10' high walls 30' x 20 ' supply and erect for 13,500. That does not include the base which I'll have to sort myself. I reckon I'd build a proper block shed with tiled roof for less than that.

Steel will be very hot even with the insulation already stuck/sprayed on because of a feature called Decrement delay.
http://www.greenspec.co.uk/building-design/decrement-delay/

Blown insulation is just not dense enough to stop heat or cold coming through over time.
NaturaL wood fibre insulations are much denser, giving much better performance

magicbastarder

BenAtar wrote: »

Bog standard glass fibre attic insulation over blockboard sheeting. I'm told that plasterboard absorbs / retains moisture, so should be avoided. Hence the blockboard.

cheers - i had considered using warmboard on the ceiling, as it generally has a foil barrier between the plaster and the insulation, but hadn't considered the moisture retention issue with the plaster. it would have allowed me to retain a cavity above the insulation to allow any moisture buildup to vent out though.

recipio

You can get insulated metal decking but its expensive. I compromised by putting one inch polystyrene sandwiched between two layers of standard decking and it worked a treat. I've seen people put fibreglass under felt held up with chicken wire but its not very effective and you should see the dust after a few years !
I'd go for a block build anyday over a steel shed if only for security.

Calahonda52

Agree re block over steel.
It might be worth considering the performance of insulated buildings for a moment.

If we insulate 100% INTERNALLY then all we are heating is the air and there is no temperature stabilisation provided by the structure.
If we 100% insulate externally then the walls help with temp stabilisation, with the heat loss down through the foundations.

Another down side if internal in a work shed is reduced ability to hang stuff off/ run stuff along the walls

If it were my shed I would go 9 inch solid on flat and woodfibre external insulation finished with skimmed concrete board.

Miname

woodturner wrote: »

Well I've gotten a quote for a steel clad shed, insulated roof and wall cladding, insulated small steel door and insulated roller door. 10' high walls 30' x 20 ' supply and erect for 13,500. That does not include the base which I'll have to sort myself. I reckon I'd build a proper block shed with tiled roof for less than that.

I had my original shed which was 60x 40 up for less than that with Kingspan insulated sheeting and walls to 7 ft.

duckman!!

woodturner wrote: »

Well I've gotten a quote for a steel clad shed, insulated roof and wall cladding, insulated small steel door and insulated roller door. 10' high walls 30' x 20 ' supply and erect for 13,500. That does not include the base which I'll have to sort myself. I reckon I'd build a proper block shed with tiled roof for less than that.

By the time you put down your foundation, build a cavity wall, roof it, fit doors and windows and get the outside plastered you will go past €13500!!

gutteruu

To give you an idea of costs, I just built a 20ft x 15ft shed out of cavity blocks. Big RSJ, plastered, PVC coated steel roof, insulated steel doors, bit of insulation in roof for 4.5k. The base cost me 850 all in which included a lot of fill and a few rows of footings. I plan to insulate the inside at some point.

Even if the cost worked out the same for both, a block built shed would be a lot better IMO.

Miname

duckman!! wrote: »

By the time you put down your foundation, build a cavity wall, roof it, fit doors and windows and get the outside plastered you will go past €13500!!

A portal frame 20 x 30 with 12' eves sheeted to 7'will cost about 4-4.5 k with insulated sheets, gutters and flashings. 1500 would have the block work and plastering done.materials included 1100 will buy most electric roller doors. Let's say another 1200 for a concrete base . 250 for a window. There's still a fair bit there to put up curtains, dry line or do whatever other fluting around has to be done.

woodturner

A good friend and neighbour of mine is a block layer. He said he'd look after me if I mixed the mortar. My brother and I would be doing the roof and a friend of his doing the plastering.

Hootanany

Timber frame is the way to go mine is 28' x 14' exterior cladding breather membrane rock wool insulation 18mm TGV internal nice and toasty

woodturner

Hootanany wrote: »

Timber frame is the way to go mine is 28' x 14' exterior cladding breather membrane rock wool insulation 18mm TGV internal nice and toasty

Have you any photos? I'd like to see how it looks.

gutteruu

Hootanany wrote: »

Timber frame is the way to go mine is 28' x 14' exterior cladding breather membrane rock wool insulation 18mm TGV internal nice and toasty

Also, just out of interest, what sort of money did it weigh in at? I was considering it but went for block. Always wondered the price difference.

Hootanany

About 4.5K shall post pic up in a while