What type of concrete blocks to buy?

[Danturboc]

Just a quick one, what type of concrete blocks should I be buying for my single skin garage build?

I know I need the Dense 7N blocks for upto DPC, but then what to use above? I can't actually find any 'Normal' Concrete blocks?

I have a selco account and Bnq trade point and they both have the 7N blocks but no others that I can see?

Any help appreciated

 

[tomfe]

I'd use a light concrete block to save your back.
Or if you are feeling manly hollow 215mm block (I don't often feel men) (27kg)
Any builders merchant will have these, more expensive than a dense concrete block though.

 

[hansPulesh]

How big will the garage be? How much weight will be pressing down on the blocks? To be honest, the breeze block type blocks always seem to crack and are pretty useless for hanging shelves etc off of. I'd go with the proper concrete blocks and render them on both sides - they're not hugely more expensive but at the same time, they are much stronger.

They are also very heavy though as someone has already mentioned. So I'd take it nice and slow with them.

Oh and lastly, I've always found Selco/B&Q/Wickes etc quite expensive. Write down a 'parts list' and find yourself a builders merchants. I'm pretty sure they'll be much cheaper than the shops already mentioned and will more than likely give you a discount too if you're buying in bulk (which you will be).

 

[Danturboc]

Thanks guys, it's roughly 22ft x12ft and will be 2.5m high. As you have said I don't really want to use breeze blocks as they aren't strong enough.

If I did the whole garage in the 7n dense blocks would that be ok? Any reason not to other than that they are heavy?

B&q were about £80 for a pallet(72) and I think Selco were about the same.

 

[^woody^]

There is no advantage at all in using 7N blocks as opposed to a 3 or 3.5N concrete block. They will crack just the same if the foundations move, so are not stronger.

Just look for ones with a smoother face for painting if need be

 

[Danturboc]

Ok, I'm going to render the outside eventually. Cheers

 

[hansPulesh]

What sort of soil do you have in the area where the garage will be built? Also, will it be built next to your house? At the back of the garden?

 

[Danturboc]

My foundations are allready done and concretes in. It's at the back of my garden

 

[Danturboc]

Got the concrete in today, it used a hell of allot more than it should of done because of the trench being 'slightly' bigger in places, think he said it was just under 6cubic metres worth! I paid £420 all in and they levelled it for me too using my new spirit level.
Some pics:












The guys were dead helpful and barrowed it all up the driveway which has a slight hill on it too!

 

[Danturboc]

Sorry I should of put pics up first, that was from my other thread that I had open, you can see my foundations there.

 

[tomfe]

So what is the difference between a 'breeze' block and a concrete block apart from 'breeze block' is a brand name concrete block which is no longer made?
There is no reason not to build it in dense concrete blocks, go ahead and use them, they are the cheapest option (at about 60p a block) and then are nice and strong and they bed down well.
But light and med concrete blocks would work just as well, they are about 10p more than the dense block, they don't crack unless you are doing something wrong, you must be thinking of aerated blocks. I know what I'd use but it's only about 250 blocks so you can save your self £25 by going with a dense block.

You got a very good deal on your concrete, £70 m£ barrowed is very cheap round our way. Though I am not completely sure why you did not take the trench all they way around....

 

[tony1851]

If you are not careful with the aerated concrete blocks, you will get vertical shrinkage cracking, particularly if it is a long wall.

 

[Danturboc]

I'm gonna go and speak to my local tracks Perkins Tommorow and see what they have to say, there usually really cheap when I have been in for other stuff.

As for not doing the trench all the way round I was advised on here and other places that there's no need to concrete under the door opening so I didn't bother to save on concrete.

Yeah the concrete was a great price, I work next to the concrete place so they know me quite well and he did me a good deal.

 

[r896neo]

If you use lightweight blocks you will love them for a few days up until the moment you finish laying them. Then you will spend the next 20 years regretting not using a block which doesnt crack joints and crack render and is not crap to make secure fixings into.

 

[Danturboc]

Yeah I'm not gonna use the lightweight ones.