Hi,

We moved into a cottage last year which has an old steel framed agricultural building about 3m away from the cottage. This building is approx 10m x 10m x 3m to eaves and 4m to apex. It's a "portal frame" structure with steel I beam columns and rafters and large timber eaves beams, purlins and rails. It is covered in galvanised, corrugated steel skin with concrete corrugated roof panels. It has a concrete floor but this has clearly been laid in different layers and is at various levels and is generally poor quality.

So, we are considering replacing it with a new building since we hope to live here for as long as our health allows us to keep the place (48 yrs old just now so hopefully 20+ yrs). As part of the replacement we hope to increase the length of the shed by 2-3 metres assuming the planning folks don't object.

I've had a quote from two companies so far - one company will take care of everything from kit manufacture to erection to laying the floor slab. The other company is a "kit only" supplier who give you the names of a couple of local contractors who will do the install. Also, the first company will do a traditional portal frame steel + timber construction with concrete foundations and the floor slab laid at the end whereas the second company produce an entirely steel structure which is cold-rolled, lighter weight steel and is bolted to the floor slab which is laid first.

Our intended use for the shed is mainly as a workshop where I intend to install a 2 post lift and will have the usual work benches and various bits of equipment plus storage. We'll also keep a corner of it as a stable since we intend to keep some small livestock such as sheep, goats, alpaca etc. Nothing large like horses or cows. We would create internal block walls to avoid these animals damaging the building skin. We also want to use a corner of it as a home gym and I'll probably create a timber stud wall and false ceiling to make this a bit cosier and cleaner.

So, I'm looking for some advice on how to think about these two different steel building construction methods and whether the higher price of the heavier duty, full portal frame structure is worth it for our usage. I'm also keen to understand the longevity of the two types of building because I'd hate to get 20-25 years down the line and be about to sell the house only to have a shed which is in need of replacement. So we're looking for a building that will still be in good shape in 20-25 years time.

Also, we have the option in both cases of going for single skin steel cladding and roofing, or to get 40mm composite insulated cladding and roofing. The price difference is substantial but I definitely don't want a building that is too cold to use for 4 months of the year and too hot for 2 months of the year, or a building that is constantly dripping condensation on us! Has anyone built a shed with this type of insulation and would you recommend it over, say, spray foaming the inside with closed cell foam afterwards?

The two companies I've had quotes from are RWHB Ltd and Premier Steel Buildings respectively and the prices are around £40k for the former and £24k + floor slab + installation for the latter (all inc vat). This is for 40mm composite insulated options in both cases and includes one roller door and one pedestrian door. No interior or electrics are included.

Any thoughts on the above or advice based on personal experience? Obviously I'll get more quotes once I decide which type of structure to go for. I have built a steel shed (23' x 10' using the lightweight non-timber method before and it was fine but the structure of the shed we have now is much heavier and I imagine would last much longer.

Edit: I should also mention that another option is to just renovate the existing building because the steel structure is still sound albeit rusty, and the timbers look to be fairly good. So we could just scrub down and paint the steel, treat the timbers with preservative and spray foam the interior cladding and roof to provide insulation. I could cut out large pads in the floor and reinforce and pour with fresh concrete to provide pads for the 2 post lift and I could use self-levelling compound elsewhere to level up the floor to make it a bit more pleasant to work from. I'm just not sure if this is going to cut it for the next 20+ years.

Thanks all,
Craig.

[Edited on 14/2/2021 by craig1410]

We bought a house with a massive cattle shed built by Steadmans at Caldbeck near Wigton it would’ve worth talking to them as they have built hundreds of sheds and make their own profiled sheets and all of the fabrication work.
The animal section will no doubt cause dust smells and noise my first thought was to extend existing by putting animal section on the end in an extension- Yorkshire board etc which might give mezzanine storage for straw etc
Atb
Mike

The eiffel tower was built in 1887 and the forth Bridge in 1883, both are made of steel (or is it cast iron) and are still standing. OK so we're not comparing apples to pomme de terres but you get my drift.

How bad is the rust?
It maybe worth getting a professional to look over and assess cons, including the foundation and opinion on what you plan to do do to it. If the building was done properly then renovation may be a sensible option.

Can’t help with the building itself but if you are going to put in a two poster I would say test how thick the concrete is at the point you are going to fit it . If the concrete isn’t thick enough it may be worth breaking it out and making a new pad the thickness of the two poster base below the finished level of the concrete , once the lift is fitted another layer of concrete to level the floor, that way there is no “ base “ to run over, makes things so much easier. Some base plates have a ramp each side which can be removed , also not a bad idea to install a drainage system under the base

I have an old zippo two Post lift, it has wide feet so you cannot get the centre of gravity outside these, the cheap lifts seem to have a 10” square plate that just bolts to the floor. Mine is much safer, it may be 30 years old and I have replaced the load nuts but even with my xc70 on it it hardly sways.

As above when I move house I will bury the feet and centre section as pushing over the 1.5” box is awkward especially when using a gearbox Jack as it’s gets in the way.

Watching this with interest as I am looking to buy a house with a barn.

Hi guys,
Sorry I didn't reply before now but I think I tried to reply when I got the email notification of replies but the site was down at the time. After that I probably forgot...

So anyway, we've done a bit of head scratching and I think renovation of the shed with possible extension later is the most likely direction. The steel frame is rusty as I mentioned but if you rub a bit of sandpaper over it for a few seconds it cleans up fine with hardly any pitting. The steel is about 1/4 inch thick and has probably been there for 25 years already so should be fine for another 25 years+, especially if I clean it up a bit and coat it in some sort of paint/protective coating to preserve it.

I need to inspect all the timber thoroughly as there are some very chunky (10"x3" I think) beams connecting all the steelwork and although I think they are largely intact, there are some areas that might be damp due to the odd roof leak etc. Again, if it's basically rot free then I'll apply some penetrating preservative during renovation.

The exterior cladding is rough and not very attractive, especially as there is a section on the front which used to have some sort of lean-to attached and that section has a break in the cladding, exposing an old limestone wall behind it. For this section we would be looking to prop the roof and remove the old wall and then reinforce the steel since the wall is about 2 feet thick and is crumbling. Better to just remove it to gain space and remove a maintenance issue.

We looked into re-skinning the shed with some sort of plastic coated galvanised steel but our current thinking is to go for a timber clad because we saw a shed recently done this way and it looked really nice. Ideally we'd get western red cedar from Canada but it's pretty expensive, upwards of £55/sqm. After a bit of research I found a potential alternative in "Thermowood" which is essentially Scot's Pine which has been heat treated with high temperature steam to change the characteristics of the wood and make it much more stable and durable. It's about half the price of Western Red Cedar and has a service life of 30 years or so. You don't need to paint it and can either let it silver due to sun exposure or you can apply a UV protection coating to retain the colour. A couple of other benefits of timber cladding is that it's fairly easy to install and I could therefore do the work myself in a progressive manner by just removing a sheet of existing cladding and then treat the underlying steel and timber frame before adding a few planks of cladding. The other advantage is that timber cladding will provide some degree of insulation (both sound and heat) which a steel skin won't provide. So I can perhaps avoid the need for expensive wall insulation and avoid condensation issues.

As for the floor, I'm leaning more towards a 4 post lift (possibly the Automotech AS-4T36) partly because of my questionable concrete but also because I currently have my Locost sitting on a the floor next to where my lift will go and there is only one vehicle door so if I install a lift then I won't be able to store the Locost next to it any more. I would need to create a second vehicle door which might not be possible due to the steel structure. So, if I get a 4 post lift then the Locost can be stored on the lift and raised up to the top when I'm not working on it or any other vehicles. And that also gains me a nice big area for machines and work bench etc which might remove the need to extend the shed. In fact the 4 post lift I'm looking at is called a "Parking Lift" as it's designed to allows cars to be stacked in this way.

Unfortunately there appears to be a steel and timber shortage in the world at present so that might delay my plans a bit. Then again I'm told the best time to install cladding is in the autumn/winter so maybe the long lead times might work out okay.

Will keep you posted.
Thanks again.