Laying a big concrete slab to level.

[doobin]

What does everyone find the easiest method? Normally we'd shutter the sides and just pour and tamp, but this slab is something like 8m x 10m. I'm thinking I'll need some kind of screed rail in the middle, plus something better than a straight ish length of 2x4 to level. I have plastic screed chairs, but not sure they'd be strong enough? Is there some kind of screed chair you can get that sits on some rebar you knock into the ground? Have plenty of space each side of the form to pull a scaffold pole out as we go.


Also, does anyone use one of those Honda powerfloat things? Are they worth it?

 

[GazCro]

K form and screed with a proper beam screed if you've got formwork to run on.
When you say honda power float do you mean a power float to finish it or one of the little "magic screed" jobbies?
You can get beam screeds long enough for 8m width but finding somewhere to hire from could be more hassle and cost than splitting it in two. Roller screed another option, it depends what its for and how important finish is?

 

[doobin]

I've got a few coming up, so I don't mind investing in the right kit to do a decent job. I was thinking of the magic screed things.

That K form looks magic, thanks!

 

[doobin]

The roller strikers look good. Has anyone here got one and could measure the wall thickness and diameter of the roller tube? I'd put a pound to a silver pig that I could make a tube to the size I want for less than half the price they want. Already have hydraulic power packs, so looks like I'd just need handles and a vibrating poker.

 

[diggerjones]

I've got a 6m roller here and the handles. The pipe is about 5mm

 

[doobin]

I've got a 6m roller here and the handles. The pipe is about 5mm

About 140mm diameter overall? and 5mm wall thickness then?

 

[GazCro]

I've got a few coming up, so I don't mind investing in the right kit to do a decent job. I was thinking of the magic screed things.

That K form looks magic, thanks!

The magic screeds are ok if you are flooding the job with pi** wet conc and just wanting to buzz about on the top but imho something to actually screed off is far superior. Rollers leave a nice finish for shed bases etc but they dont tamp. For some reason beam screeds are seemingly becoming the less popular option but if you've got formwork to run on they will compact conc to about 150mm and leave a decent finish (bull float or power float after if you want).

 

[doobin]

The magic screeds are ok if you are flooding the job with pi** wet conc and just wanting to buzz about on the top but imho something to actually screed off is far superior. Rollers leave a nice finish for shed bases etc but they dont tamp. For some reason beam screeds are seemingly becoming the less popular option but if you've got formwork to run on they will compact conc to about 150mm and leave a decent finish (bull float or power float after if you want).

You'd go for beam screed over a roller striker and vibrating poker?

I want the thing that'll do a decent job, but the roller striker looks so much 'handier' and easier to sort different lengths for without having to sell a kidney!

Edit- found a great thread on the old forum (insert nostalgic smiley): http://www.ceforum.co.uk/showthread.php?t=4415

 

[GazCro]

You'd go for beam screed over a roller striker and vibrating poker?

I want the thing that'll do a decent job, but the roller striker looks so much 'handier' and easier to sort different lengths for without having to sell a kidney!

Personally yes but as you say beams are probably dearer than a length of tube. You really need to screed first with a roller anyway as the tube tends to ride over the conc unless you keep raking excess away from it. The thing to be aware with roller is that if you pass over too much you'll actually end up low in the middle.

 

[Giles]

I’ve got rollers, and magic floats and power floats horses for courses.

yards etc we use our roller striker if use k form at 5m intervals gives you your contraction joint as well that you then fill with polysulphide. Does require a few back snd forths and keep the shutters clean. Or we use dished channels to form the bays.

bigger slabs in sheds with walls up etc we use laser on bad plate guy with trowel sets a square to height then pull the magic screed over it. Generally use 3m/5m 8m to big free floating. You can now get lighter battery ones which look great.

my mates got laser screed but can’t ride over rebar in rafts etc

roller tamper and magic float we still use bump cutter, roller tamp, and magnesium bull float on them then joint cutters to form wet joints think they’re nicer than saw cuts.

can get Upto 10m roller strikers but you need the bigger 40l/min power pack for anything over 7m I believe.

roller you need 4 guys two on handles and two good rakers.

hate the beams, heavy Abd hard work and unless you’ve got really strong shutters they shake the s**t out of them. Needs to be metal road forms ideally.

 

[Giles]

Also once worrying about a big pour that had to be flat bought a belle 9m tamp worse thing ever big horrible bastard still got it keep meaning to cut it in half use it as straight edges etc

 

[diggerjones]

About 140mm diameter overall? and 5mm wall thickness then?

Yes. Just looked and your about right. We've done lots of yards. 2 of us. The roller will pull alot off. Leave it spinning and keep going back and forth till down to road form

 

[Giles]

Replacement Bare End Striker Tube

Purchase 'bare end' striker tube to create your own desired tube lengths.

www.speedcrete.co.uk

 

[Monkeybusiness]

@doobin - cancel the Multi-one and buy one of these instead - awesome machine, poured 60m3 as fast as they could get the wagons in and it is dead level!

 

[Left hooker]

@doobin - cancel the Multi-one and buy one of these instead - awesome machine, poured 60m3 as fast as they could get the wagons in and it is dead level!

A guy from exeter I know has one of those for large floors he does in the sheds/warehouses he puts up

 

[Giles]

@doobin - cancel the Multi-one and buy one of these instead - awesome machine, poured 60m3 as fast as they could get the wagons in and it is dead level!

3 guys near bought them, 2 gone bust one still at it but that’s all he does say in day out all over. Other guys just used them in their jobs but some of them £70k new with all machine control stuff. We’ve used them on jobs and it’s lot easier to hire him in with his machine for the odd big pour. Lads we use also had the bulldozer one for pushing it around before levelling

 

[Monkeybusiness]

3 guys near bought them, 2 gone bust one still at it but that’s all he does say in day out all over. Other guys just used them in their jobs but some of them £70k new with all machine control stuff. We’ve used them on jobs and it’s lot easier to hire him in with his machine for the odd big pour. Lads we use also had the bulldozer one for pushing it around before levelling

Yeah - the lads who did my floor build farms all over the country and pour a lot of concrete - I think that machine is kept pretty busy on their own work (and undoubtedly saves them a massive amount of time/labour).

 

[doobin]

Where's the best place to get K-form and mesh from?

 

[Giles]

Where's the best place to get K-form and mesh from?

Burdens aka wosleys generally have the k form

mesh local as possible I just paid £52 for a proper a393 10mm sheets that’s 4.8x2.4 not the merchant size ones which are 3mx2m approx

 

[GazCro]

Where's the best place to get K-form and mesh from?

You'll know you're own area best as to who ring tbh. It'll depend on quantity you might get it cheaper online for bigger orders but small orders delivery will hike cost up. Mesh is often cheaper off steel suppliers and in full size sheets but they might not be as happy to deliver for pence as you're local builders merchant.