epsilonGreedy

Strength of single skin decorative brick bonds.

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Does the high proportion of half bricks in a decorative bond, specified for conservation requirements, compromise strength?

 

I am asking this question in the context of a standard two story brick house with a tied block inner skin. The type of bonds are English, Flemish, Garden Wall etc.

Edited by epsilonGreedy

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None at all. Bonding strength of the mortar is key as are staggered joints. 

 

Two storey is fine assuming properly tied to the main inner skin. 

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If you’re going down this route I would advise getting some test panels built in the different bonds by your brickie & having a good look. 

What Ive found with certain metric bricks is that the relative proportions of a stretcher (full brick) to a header (half brick) can give an unsatisfactory effect in Flemish bond,compared to imperials. 

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The inner and outer walls will be tied.

 

Once of the concerns that prompted my question is the brickwork of a house in-build that I have been visiting. The brick laying team seems tidy and conscientious as far as  can judge but the half bricks look irregular from the cavity side. They are producing their half bricks from full brick splits, to make matters worse the full bricks have three hollows tubes and as a result the bricks are splitting 55/45 or maybe 60/40.

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If you are that worried then specify in your brickwork tendering that all splits must be machine cut. 

 

Its not a big issue - that is the least of your worries ..!! 

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Also get them to sample panel an expansion joint. Loads I see in bonds put header & quoin closer up to the expansion & it looks wrong to me. With a couple of exceptions (chimney cornel,next to a stone mullion for example) the only place you should see a quoin closer (quarter brick) is next to a quoin header,so at the corners & window or door reveals. 

 

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On 2/7/2018 at 10:28, PeterW said:

If you are that worried then specify in your brickwork tendering that all splits must be machine cut. 

 

Ok. Having looked at brick cutting videos on YouTube I noticed that the cutting process munches away a measurable percentage of brick bulk, at least it could be a consistent munch rather than the irregular percentage split from a manual whack to a brick.

 

On 2/7/2018 at 10:28, PeterW said:

Its not a big issue - that is the least of your worries ..!! 

 

Part of the learning curve is discovering where to focus my worries.

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2 hours ago, epsilonGreedy said:

Ok. Having looked at brick cutting videos on YouTube I noticed that the cutting process munches away a measurable percentage of brick bulk, at least it could be a consistent munch rather than the irregular percentage split from a manual whack to a brick.

 

My diamond Stihl Saw blade is 2.5mm thick so on a standard brick that is slightly more than 1%.... Its the time more than anything however @Brickie will be along shortly but if he does what we do then we line 10 up at once in a jig (yes this is an old pallet offcut) and cut the lot at once. Clean straight line and no idiot labourer holding the brick with his foot when he has the Stihl saw 2 " away....

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If you’ve a two storey building to do you’re going to need so many that it’d be worth hiring a bench saw with the diamond blade & water feed. 

Your Labourer/bucket carrier/fool will get a lot more done & possibly was born with extra digits so can cope with potential loss of a couple. 

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For labour? 

If the half batts were pre cut for me I’d want 33% more,at least. 

There are 78 units /sq m in 100mm Flemish bond compared to 60 for stretcher,plus much more care needs to be taken when setting out to achieve as good a bond as a possible in the piers between any openings & also you really need to keep your perps (cross joints) near as dammit plumb all the way up. Stretcher bond is quite forgiving of a little variation here & there but it shows up strongly in Flemish. 

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So you would also need a brick saw and a bloke on it for a couple of days if you need nice neet cuts instead of just snapping them. 

Is this a stipulation of your planning @epsilonGreedy Or do you just fancy a bit of Flemish bond. 

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It is a planning stipulation, I am beginning to appreciate this is not a cost that a team will absorb to get the job.

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Cheaper than a table saw (but not so neat) would be a ‘blockbuster’-you’ll see paving gangs use them & brickwork gangs using 140mm blocks. You can sit it on something so it’s at a comfortable height & line up at least 4 bricks at a time in it,so getting 8 batts every time. 

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Fwiw I bought these to cut all my bricks in half. Bit dusty but it did the job well 

https://www.toolstop.co.uk/index.php?option=shop&page=shop.product_details&product_id=16012&l=uk&utm_source=google&utm_medium=base&gclid=EAIaIQobChMI2P6izqqj2QIVz7ftCh29_AqNEAQYASABEgIxjfD_BwE

 

https://www.toolstop.co.uk/evolution-db355-rage-2-diamond-cutting-blade-355mm-p14004

 

its an old video so I opologise about the quality. But here it is in action. 

 

Skip to 11:30 for the actual brick cutting 

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When you asked previously about how you could help on site,

this is something you could do very easily 

hire the table saw and spend a couple of weekends cutting all the half’s, after you have done 20you will be an expert, 

you could even cut all the closers for them, this could well be a good bit of help and sweeten the deal with the brickies , 

it will still cost more than stretcher bond, but there’s not a lot you can do about that. 

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On 2/13/2018 at 18:04, Russell griffiths said:

When you asked previously about how you could help on site,

this is something you could do very easily 

hire the table saw and spend a couple of weekends cutting all the half’s, after you have done 20you will be an expert, 

you could even cut all the closers for them, this could well be a good bit of help and sweeten the deal with the brickies , 

it will still cost more than stretcher bond, but there’s not a lot you can do about that. 

 

As you say, something I can do hands on without a long learning curve. The brick manufacturer quoted £0.20 per cut today but that will be £1000 for the 10,000 half bricks I need.

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Have you a choice in bricks or are you controlled by planning, you could drop a right clanger if you pick something that is a bugger to cut 

do a few test cuts with a simple grinder and diamond disc to get a feel for how well they cut

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1 hour ago, epsilonGreedy said:

 

As you say, something I can do hands on without a long learning curve. The brick manufacturer quoted £0.20 per cut today but that will be £1000 for the 10,000 half bricks I need.

 

Thats not a bad price tbh. If you work on 120/hr to cut then that’s about 84 hours cutting. By the time you have factored in a decent diamond wet table and disk for 2 weeks plus wastage and the stacking / sorting of 10 pallets of bricks and the fact you have only what you need to buy, then £1000 in the big scheme of things is rounding ... 

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Would it not be 5000 cuts as each cut makes two halves so 5000 bricks cut in half equals 10000 headers 

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7 minutes ago, Russell griffiths said:

I haven’t tried to work it out but 10,000 headers sounds a lot. 

 40 headers and 40 stretchers to a metre would make it 250 sqm. So not unreasonable for a 12x12 with 5m wall height measured through. 

 

And yes, 5000 cuts not 10000..! Long day .. 

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What’s the local norm-is it all Flemish bond & that bond is non negotiable?

Reason I ask is I’ve long had a small cheat in my head for false (4”) English bond but I’ve not had a job to test it out on as yet. 

It occurs to me that it would be possible with a cutter to cut a false joint out of the stretchers,giving the impression of two headers once jointed. So,on the header course,once the quoin header & closer are laid you’re just laying stretcher after lovely stretcher,cutting the labour cost hugely not to mention the handling & cutting. 

So,if there’s a lot of English bond local to you & you like the appearance,maybe you could make a case for this?

Edited by Brickie
Typoo

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1 hour ago, Brickie said:

It occurs to me that it would be possible with a cutter to cut a false joint out of the stretchers,giving the impression of two headers once jointed.

 

That is exactly what I did on my existing house when I blocked up some windows. Matches the original perfectly.

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On 2/14/2018 at 18:44, Russell griffiths said:

Have you a choice in bricks or are you controlled by planning, you could drop a right clanger if you pick something that is a bugger to cut 

do a few test cuts with a simple grinder and diamond disc to get a feel for how well they cut

 

 

Yes the house details are highly prescribed by the local conservation officer, I even have a mandated colour code for the front door. Should Disney ever film their own version of Pride & Predudice this house will be perfect.

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