epsilonGreedy

Beguiled by thin-joint.

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I have become seduced by the wonders of thin-joint blockwork in the last 24 hours and I blame @Brickie when in another thread he advised a single skin of regular blockwork should not rise beyond around 3 to 5 courses without temporary support, unless he added it is thin-joint. This comment led to much YouTube research on thin-joint.

 

My problem is that with special heritage bricks suffering long production lead times I might be waiting 3+ months to progress my build above the beam & block ground floor. It is claimed that thin-joint blockwork can progress to 2-story gutter height as a single skin, then a roof can be loaded on this single skin structure before regular brickies catch up and reinforce the inner shell with a facing brick tied cavity wall.

 

I would not place that much faith in the thin-joint system and put the roof on but I could envisage spending August/September building up my walls to the point that the first floor joists can be fitted.

 

There must be some negative aspect to the thin-joint system?

Edited by epsilonGreedy

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I think it is just Thermalite type blocks and you may need special ties as if they are standard size they don't course with standard size bricks.  The first course needs to be spot on - laid in mortar.  The rest looks easy (at least it does on YouTube).  I guess the coursing thing may be an issue with openings as well but the blocks are easy to cut.

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First four courses have to be laser perfect in plumb as if they aren’t you can’t easily correct an issue. Easier with wider blocks - thin joint originally was designed for 215mm blocks - as you can get a level across them too. 

 

It’s openings you struggle at as either you need to switch back to commons and splits for lintels or your bricks and blocks don’t match up. 

 

You may also end up going with twin lintels too as with nothing under the front edge they will have a tendency to twist. 

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3 minutes ago, Mr Punter said:

I think it is just Thermalite type blocks and you may need special ties as if they are standard size they don't course with standard size bricks.

 

 

Yes the blocks can be used with regular mortar, the magic ingredient is the thin cement glue that is chemically closer to a tile adhesive I believe. The resulting inter-block bond is 4 times stronger than a regular sand/cement mortar, hence the single-skin structural stability up to say 5 meters high.

 

Rob Songer has published many brick laying videos on YouTube and in the past I have got the impression he is a level headed expert. Yesterday I discovered his 6 videos on thin-joint and he seems to be a proponent of thin-joint when reading the comments.

 

https://www.youtube.com/watch?v=YHBnNQ4_D14

 

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I have Porotherm which is thin joint.

 

Much as large areas of straight wall went up quickly, as soon as you had door openings etc it was no faster than normal blockwork. Indeed it was probably slower as the brickies weren't used to it. By far the biggest time over run on the build was the block work.

 

The SE wanted us to prop the two leaf cavity wall ground floor before putting the first floor concrete slabs on it. Much as theoretically you can build a single leaf wall, I seriously doubt that they would recommend this for safety.

 

It is quite easy to cut, but it is harder to fix things to.

 

If you want to build a house then face it with brick, the fastest way is going to be SIPS or timber frame. They can be built to roof level and the roof put on before the outer skin. You also won't have the issue of matching the course heights as mentioned.

 

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3 hours ago, AliG said:

I have Porotherm which is thin joint.

 

Much as large areas of straight wall went up quickly, as soon as you had door openings etc it was no faster than normal blockwork. Indeed it was probably slower as the brickies weren't used to it. By far the biggest time over run on the build was the block work.

 

 

Good to hear firsthand experience even if ambivalent, I need to be aware of the negatives. Porotherm looks to be based on clay blocks and the perp joints are dry because a moulded lug replaces thin mortar on the perp joints. Is this the original European thin-joint block system?

 

Speed of laying is not the issue in my case, I would be adopting it to avoid a 2 or 3 month idle phase on my project.

Edited by epsilonGreedy

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Only ever done it once & didn’t get much guidance at the time,so found it a PITA. 

I’ve seen brickies on Social media swear by it though. 

Things I would want to research would be expansion joints,advice on how many courses to go at a time,things like that.

As was mentioned on another thread-are you really sure this is going to be a consideration? I.E. have you made a rudimentary programme of all the Site activities (not to mention the off site hoops that need jumping through) between now & you being at the stage where you need facing bricks on Site? Which is normally,foundation blockwork in,ground floor structural slab or b&b in,drainage in,,Site power on,welfare facilities sorted. I know the brick lead time seems daunting but it’s amazing how the weeks can fly by just getting yourself to that stage. A bit of bad weather,some unforeseen problem in the ground,a utilities contractor not being available when you want them or taking ages to do their bit-there are so many things that can slow progress down at the start its unreal. 

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3 hours ago, PeterW said:

It’s openings you struggle at as either you need to switch back to commons and splits for lintels or your bricks and blocks don’t match up. 

 

 

Indeed it is the workflow around openings that I cannot picture at the moment. The blocks are easy to shape but ensuring the following facing bricks are simple whole multiples will require some precise maths and double checking. My building control chap said he will ensure masonry panels and apertures are sized to whole facing bricks.

 

3 hours ago, PeterW said:

You may also end up going with twin lintels too as with nothing under the front edge they will have a tendency to twist.

 

 

I can picture the problem you raise, what do you think of the Rob Songer method illustrated on YouTube where he attached a temporary wooden plinth each side of the opening on the external wall to support the 200mm of unsupported lintel?

 

https://www.youtube.com/watch?v=SDovS2azbNg

 

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6 minutes ago, epsilonGreedy said:

can picture the problem you raise, what do you think of the Rob Songer method illustrated on YouTube where he attached a temporary wooden plinth each side of the opening on the external wall to support the 200mm of unsupported lintel?

 

How do you do first floor ..?? Can’t prop from the ground. 

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5 minutes ago, PeterW said:

How do you do first floor ..?? Can’t prop from the ground. 

 

 

I only intend to go two courses above the first floor joist hangers so not a problem in my case. I wonder if he just reaches around from internal scaffolding and glues those wooden plinths in position with thin-joint cement?

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Are you trying to solve a problem that might not occur 

 

get your brick order in now 

 

if you are doing your own brickwork then you need to get up to just under your block n beam

you then need to fit your block n beam

then you can bring your inner skin up to window chill height. 

 

Have you put a realistic time frame on this, you may find it takes longer than you think, factor in a weeks holiday to get over the stress, and bada bing, bricks arrive 

have you had a firm delivery time. 

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Thinking about the thin joint system that could definitely be the way to do the inner skin 

as an inexperienced bricklayer it looks like it will help you out

 

i was going to post up something about evil procrastination 

procrastination has just cost me a full days work, as I sat and doodled endless sketches of wall design, working out that one method would be £100 cheaper but would take 3-4 hours longer. 

All I know is two things it wasted a whole days labour, when I ran my own company it wouldn’t have happened I would have ordered the blocks and been laying them the next day, I think we can all be accused of over thinking and procrastinating because it is our own place. 

 

So order that thin  joint and crack on. 

 

 

 

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Remember with Thin Joint, its the special blocks which are slightly larger, and made in a different factory which has more precise equipment, that can have a lead time also. I used thin joint for our extension, and it was a joy to build.

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On 14/06/2018 at 18:36, Mr Punter said:

I think it is just Thermalite type blocks and you may need special ties as if they are standard size they don't course with standard size bricks.  The first course needs to be spot on - laid in mortar.

 

 

Yup, the ties are very different and when skinning a completed internal thin-joint wall with facing bricks the ties are drilled into the low density inner blocks with a special tool that ensures a specified depth. Because the ties can be driled anywhere into the internal block there is no concern about course alignment at this step. Rob Songer emphasizes the drill angle should be upwards towards the inner block to ensure cavity moisture runs outwards.

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On 15/06/2018 at 09:55, MikeGrahamT21 said:

Remember with Thin Joint, its the special blocks which are slightly larger, and made in a different factory which has more precise equipment, that can have a lead time also. I used thin joint for our extension, and it was a joy to build.

 

 

Since starting this thread I have found that H+H offer a self builder's estimation and supply service. The whole package is delivered to a local BM so some de-risking here for a first time self builder.

 

I also read somewhere that special thin-joint block sizes at 75mm multiples were offered to help maintain course alignment with facing bricks but cannot find examples. Maybe with new drilled in wall ties, course alignment would be a bad thing.

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1 hour ago, epsilonGreedy said:

Since starting this thread I have found that H+H offer a self builder's estimation and supply service. The whole package is delivered to a local BM so some de-risking here for a first time self builder.

 

 

Just be careful with this that you can return any overage to the BM for credit as I expect they will do the standard +10% wastage that means you may have up to 2 packs left over on an average build. You could end up stuck with those if it’s a non-stock item.

 

Estimating services tend to measure through all openings and then add a bit - careful cutting means you can usually use pieces for ends and openings and self builders are a bit more careful with re-use. I have a rule that anything over a half block is stacked for cutting and re-use as otherwise it’s just straight in the skip. 

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On 15/06/2018 at 08:21, Russell griffiths said:

Thinking about the thin joint system that could definitely be the way to do the inner skin 

as an inexperienced bricklayer it looks like it will help you out

 

i was going to post up something about evil procrastination 

procrastination has just cost me a full days work...

 

So order that thin  joint and crack on. 

 

 

I might be giving off procrastination vibes so timely advice. Things are happening behind the scenes:

  1. The foundation digger man is booked.
  2. Concrete ordered dig + 2 days.
  3. Got an even lower price on the concrete because wise old owl builder says the concrete wagon will have no problem on my now very firm green field hence no need for pumpable stuff. Concrete supplier is going to pop around and double check ground condition.
  4. Wise old owl semi retired builder is loaning me his £600 laser for the setting out levels levels.
  5. Meeting building control inspector on site this Thursday.

Now I have time to speculate what happens above dpc.

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11 minutes ago, Russell griffiths said:

So how is the brick ordering going

what is the current wait time. 

 

I have been thinking about side stepping the fancy brick heritage supply problem through a different build technique, see my Plan-C thread. This is only a day old and not looking like a runner at the moment.

 

Got some queries on bricks ongoing at the moment, 10,000 mid September is the best at the moment.

 

How quickly could a 2+1 brickie team get these facing bricks up if the inner thin-joint wall advanced a few courses ahead of them? My thinking is that with an existing inner wall structure established they do not need to be concerned with chimneys, door/window aperture positioning or internal walls.

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You normally gauge the wall openings to the bricks and let the blocks follow as they are easier to cut. 

 

10,000 bricks and 200sqm of block you are talking 5-6 weeks to wall plate assuming nothing really fancy or complex. 

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I’m not sure if someone has asked this before 

have you considered a timber frame

so you can get the full structure up and roof on and then brick skin around it when the bricks are ready. 

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On 16/06/2018 at 17:38, epsilonGreedy said:

 

Since starting this thread I have found that H+H offer a self builder's estimation and supply service. The whole package is delivered to a local BM so some de-risking here for a first time self builder.

 

I also read somewhere that special thin-joint block sizes at 75mm multiples were offered to help maintain course alignment with facing bricks but cannot find examples. Maybe with new drilled in wall ties, course alignment would be a bad thing.

 

Coursing blocks can be useful for lintel heights, to be honest though I just cut mine and everything was OK, just have to cut really straight, the coursing blocks will be more expensive to buy also

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14 minutes ago, MikeGrahamT21 said:

just have to cut really straight,

A block saw is dead handy if you don’t have many to do,you get a lovely straight cut. 

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1 hour ago, Brickie said:

A block saw is dead handy if you don’t have many to do,you get a lovely straight cut.

 

 

Is this a type of handsaw? I was going to investigate if there was some form of articulated guide available that would help maintain a right angled cut into a block.

Edited by epsilonGreedy

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Yes,only any good for aerated blocks though. 

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