building extension with steel frame

[mickthetree]

afternoon all
I am designing an extension to our 1950s bungalow and considering building methods.

Does anyone have experience of building with steel frames?

I'm struggling to find the right information online to evaluate if this would be possible/cost effective/benefits.

Specifically:
If I use timber framing to in fill between the steel frame (cladding on the outside) what sort of footings are required (if any) for supporting these in fill walls?
It has been mentioned that I might need to tie any columns together with 300->400mm deep trenches with reinforcing. This makes sense to prevent spreading and if so would these be sufficient to support in fill walls?
I'd be looking to get a structural engineer to calculate the size of steels and recommend appropriate sized footings for these to sit on.
Can the footings for the columns form part of the overall ground floor concrete slab?
If I in fill some of the walls with static glass their U value will obviously be lower than a timber frame, insulated wall. How does this pass building regs?

Any experience or a nudge in the right direction as to where I might find the right information would be gratefully accepted.

 

[Wuffles]

I had a steel "goal post" extension build going on over the past couple of years at my place. Structural engineer recommended things that made the steel contractor wince - when two trades collide. Steel was specced (in the contractor's opinion) to that of a car park he'd constructed, we put it down to Structural engineer over-egging things.

We had 1m cubed reinforced pads created for the goal posts and then standard footings for the infill walls, standard block construction.

Do you have planning yet? If you do, start conversations with a building control outfit either Council or private (private will normally be cheaper) and start to take on their recommendations as you're presumably trying to avoid architect's fees, like we did.

 

[mickthetree]

Thanks for the info Wuffles much appreciated.

Private building control! Never new that existed. I'll research that tonight.

I have been warned about structural engineers over dooing it but I cant see anyway round that short of getting a recommendation of someone who actually knows what they are doing. We have a few steel fabricators I drive past on my way home so I might see if they have anyone they would recommend.

Many thanks

 

[Wuffles]

Thanks for the info Wuffles much appreciated.

Private building control! Never new that existed. I'll research that tonight.

I have been warned about structural engineers over dooing it but I cant see anyway round that short of getting a recommendation of someone who actually knows what they are doing. We have a few steel fabricators I drive past on my way home so I might see if they have anyone they would recommend.

Many thanks

I used a company called JHAI, don't know if they're in your area, but google them and you'll know what to search for.

 

[RobinBHM]

I find BBS building control helpful, much easier to deal with than local authority. Basically BBS will submit a building notice to your local authority and provided they don't have an issue, BBS are then automatically authorised to undertake the inspections and issue a final certificate on the your project.

They will cover your area.

 

[blackrodd]

Steel frame building is specialised , and expensive, needing cranes and access equipment, large footings and it will no doubt need fire protection as it will be a domestic build.
The Erectors insurances are high and have several fatalities a year, mainly from falls and harness failure.
As there is probably a ratio of several thousand builders to 1 steel erector team so will be expensive
I've applied the fire protection to many steel frame buildings, supermarkets hospitals and many B&Q, Carpetright type of buildings etc,you see on many estates nowadays.
This includes British Gypsum's Column and beam encasement, Vicuclad, fire blankets and fire stops, structural fire protection, as well as environmental protection, Plenums,etc,etc, etc, know a bit about it.
You will need structural engineers for calculations for the architect to draw from and they will carry out some site visits and when you see their fee scales you'll probably need a change of underwear!
Unless you really must use steel, stay with the conventional building methods.
Rodders

 

[mickthetree]

Hi Rodders sounds like you have some experience of this! Many thanks for the thorough insight and guidance.

 

[RobinBHM]

afternoon all

If I in fill some of the walls with static glass their U value will obviously be lower than a timber frame, insulated wall. How does this pass building regs?

It would be classed as an extension with excess glazing. It can still be done, but you need to prove that the new extension will use no more energy than if you built an extension with all thermal elements within the regulations. It requires a SAPS test which is a software simulation taking into account the complete house + new extension. If you have made any energy efficieny improvements in recent years these can count towards the overall scheme. Generally it is much easier to make old inefficient single glazed buildings comply than new ones.

If you are considering fixed glazing then you could use triple glazing, it isnt going to cost a huge amount and will reduce the centre pane u value down to under 1.0 (say for a 4-16-4-16-4 with 2 panes having soft coat).

A SAPS test cost in the region £150 -£300+vat

Is the proposed extension a complex design? Or are you just thinking of an alternative construction method to a cavity masonry structure? Have you considered a SIPS option?

If you want a vaulted ceiling, then steelwork is probably the only option, using cranked steels.

 

[AJB Temple]

We have in the past used steel frames from time to time when converting listed country houses into flats. (When I say "we", I did none of the work - I was running a property development company). I learnt enough from this to conclude that I would steer clear of it completely myself unless I was doing a new build on a clear site and had some reason for using steel. It will cost you far more for domestic building than conventional methods in my experience, needs special skills that most jobbing builders do not have, considerable precision, and expensive equipment. Looks nice and easy on programmes like Grand Designs. There may be a reason why they always go over budget. The guys above are daed right. Avoid.

 

[mickthetree]

Thanks Robin
Thats great info. We have added double glazing, replaced the back boiler and added insulation so maybe we can use that to offset the excess glazing.
I'll post a before and after of the plans shortly.

 

[No skills]

Don't know about easy on grand designs, they always seem to be lopping bits off
Even though it's not I think basic steel construction (simple square buildings) should be cheaper than regular construction methods. For example to make 4 columns..
Pick up steel with crane/gantry, move to bandsaw. Measure and cut.
Get sheet of 10mm plate (or whatever) with forklift, move to table and measure and cut with plasma.
Move cut plates to drill press, drill to suit.
Get all cut parts to assembly area, tack together - check for measurement and square, weld!!
Move new column to spray area, spray.
Repeat 3 more times...

That will certainly water off any fabricators here, but really simple square stuff should be fast and easy to make and shouldn't cost a lot.
But once your past the simple and square and into complex and funny shapes then just bend over cos that's not easy

 

[mickthetree]

The current bungalow is a very traditional 1950s semi detached build with no alterations and a large garden.

short animation of current from sketchup is here

The proposed extension is a considerable enlargement, but the downstairs is almost entirely within permitted, save for the rear corner shown in red.

This video showing the proposed also includes the adjoined neighbour albeit without roofs added.

The upstairs however is quite outside of the realms of permitted.

 

[Wuffles]

I was lucky to have a couple of steel contractors in just the next village, cost me 3 grand all in for the two goalposts which wasn't cheap by any means, but there was no other way to span the 11 meter open plan space we had planned, and as I said, it's over-specced to the max.

This isn't how I'd suggest you do anything, but this is how we did it "on the cheap" as it were:

We didn't employ an architect, plans submitted for planning were knocked up by my Wife on paper using a scale rule and scanned, but from your sketch-up skills, I would say you haven't anything to worry about there.

I m̶i̶c̶r̶o̶ project managed everything and have had my hand in all of it to save money.

Employed a farm technician who knows his way around a digger, a bricky who knew what he was doing, some roofing lads who knew what they were doing and all the overlapping bits were glued together with advice from the building control firm. We had outline plans only, no detailed drawings which always caused a few laughs, but it meant we could do things the way the trades (and the BC) were happy to do it rather than them moaning about an architect's plans.

If you are planning to do as much of it yourself as possible, one piece of advice is don't labour for a cantankerous old bricky, get in some labourers - nearly killed me.

Once the roof was on, me and some lads did everything else until the screeders came in on the cheap - they were brilliant and normally only work on commercial projects, so the tip they got completely threw them at the end - by coming in on a favour they saved me around a grand at least.

Our build came to approximately £760psqm. No expense spared though, so in the end it worked out cheaper than it could have by a few hundred per square meter.

Hope that's of some use. Don't be frightened of steel, it is pricey, but it has its purpose.

 

[RobinBHM]

Just had a quick look at your sketchup animation. Without trying to look at specifics, I would say the steelwork isnt very complicated, although there will be a fair bit of it.

As far as planning goes, you will need to understand the planning policy. Mostly planning prefers to 'match existing', especially as far as matching roof style. Thats not to say a contrmporary design wouldnt be accepted, but it will need a well considered design brief and well argued design statement.

I think the complication is how to progress the design. Theres no point making a planning application if the design cant be built and nor would you want to pay for calcs for a design that wont get consent.

 

[wolfey]

Hi, Not shore if it comes under the same thing but currently putting up a new steel frame warehouse next door to our current warehouse and the pads have just been poured and steel frame is about to go up.
If it is the same sort of system im happy to ask the steel frame guy's any technical questions you may have incase they can help...

I sadly cant as im just a joiner but they are in our unit every 5 minutes making a cup of coffee or using our bog so I can just ask!!!

Im not shore how to post pics but can try post pics of pads ect...

If not the same thing then I apologise and ignore this post...

Best

Wolfey

 

[mickthetree]

Thanks wolfey
I'd be interested to know if they do any residential work or if they dismiss steel as an option for residential and why.
if you can take a pic or two of the pads and any foundations that would be great

 

[woodpig]

I've watched a number of steel frame buildings go up and was very impressed with the speed of construction. As mentioned you can span large distances with steel as well. "Engineered" wooden beams on the other hand have always looked very dodgy to me and don't start me off on Sterling board walls! Given the choice I'd be far happier with steel construction if it was within budget.

 

[No skills]

I'm not overly sold on it myself, if I was building something with large open spans then yes. If it's more traditional design i think I'd like to do the first floor masonry and timber for anything higher. I love the way the yanks can chop and change their stick framed houses, yes I watch too much this old house.