Concrete Lego blocks and BC

[K78]

I’m guessing that building control and mortgage companies would view 300mm wide Concrete Lego blocks with ewi as no different than standard concrete block solid wall construction with EWI?

 

Am I missing something obvious? I know they are usually used for agricultural purposes or retaining walls. 
 

I never considered them for my house due to their 600mm width and 1.5 tonne weight,  but the new 300mm versions really got my thinking. 
 

I know for most they would be expensive and impractical. But labour costs for block laying I’ve had have been astronomical. This would be much cheaper for me personally as I could diy the construction with a mate and have the shell up in 2/3 days. 
 

I liked ICF blocks for the diy/labour saving aspect but any burst or collapse would be directly on to a footpath and busy road. I can’t take that risk. 

 

Thanks

Edited January 7, 2020 by K78

[Russell griffiths]

Im really not seeing why you are looking at this

what you and @scottishjohn are talking about is in principle already in use. 

You want, a concrete core with insulation stuck on the outside 

you want it easy to erect without many skilled trades

its ICF blocks, has been around for years and used by many on this forum

whatever make you choose there basically the same

stack the blocks up using very simple principles ( no forklift needed) 

fill with concrete. 

Job done

full BBA approval 

fully mortgageable 

 

im completely for thinking outside the box, but come on leave those blocks for building retaining walls. 

[nod]

I’m looking at some while I’m sat having five minutes after my daily one hour drive 

There used quite a lot for retaining walls and keeping gypsies out 

I cat seen any advantage in using them to build a house 

ICF a better option 

[K78]

On 07/01/2020 at 07:27, Russell griffiths said:

Im really not seeing why you are looking at this

what you and @scottishjohn are talking about is in principle already in use. 

You want, a concrete core with insulation stuck on the outside 

you want it easy to erect without many skilled trades

its ICF blocks, has been around for years and used by many on this forum

whatever make you choose there basically the same

stack the blocks up using very simple principles ( no forklift needed) 

fill with concrete. 

Job done

full BBA approval 

fully mortgageable 

 

im completely for thinking outside the box, but come on leave those blocks for building retaining walls. 

icf is too much of a risk for me due to my site location. I’ve been on the durisol and isotex courses.  It could be hazardous and not worth the risk. 
 

Some icf are still awaiting bba approval. Surely concrete block is standard construction regardless of the size of them? Therefor should be easier to mortgage than non standard construction?

 

Full scaffold, and multiple concrete pump hire would not be required with the larger blocks either ( they cost more than a telehandler) and the walls would be up in 2 days. 
 

@scottishjohn was talking about 1.5 tonne , 1.8m long 60 cm wide blocks. I used the for a wall. Not practical imo for a house. These are only 30cm wide. 
 

it isn’t really thinking outside the box. Some of oldest man made structures are made from huge blocks

Edited January 10, 2020 by K78

[K78]

On 07/01/2020 at 08:01, nod said:

I’m looking at some while I’m sat having five minutes after my daily one hour drive 

There used quite a lot for retaining walls and keeping gypsies out 

I cat seen any advantage in using them to build a house 

ICF a better option 

icf is more expensive and doesn’t suit my site unfortunately. The added obvious bonus with icf Is the insulation is included 
 

I had a huge retaining wall built with lego blocks in days and it saved me at least £35k (£65 k if you compare to the highest quotes I got)

 

Edited January 10, 2020 by K78

[K78]

Regardless of whether folks think other methods are better, and I do appreciate all viewpoint.

 

Am I correct in assuming this would be classed as standard solid wall construction for BC and Mortgage?

[Russell griffiths]

Can you explain the risk with ICF not really with you, and what is the risk on your site ?

if I look at the Lego blocks you are talking about I can think of so many reasons NOT to  use them, and that is without trying. 

What are you going to do regarding block length? Will you be limited to building to block sizes, if you cut a block will the next row lock on top or not. 

 

How can icf be 3 times more expensive 

are you really adding up all the elements correctly 

lets say you have built your block structure with no problems, then what?

you then need to add insulation to the outside to the whole structure, how??

you then need to cover the insulation, again how 

by the time you have brought your insulation and fixed it on you will be wishing you had never started. 

3 minutes ago, K78 said:

Regardless of whether folks think other methods are better, and I do appreciate all viewpoint.

 

Am I correct in assuming this would be classed as standard solid wall construction for BC and Mortgage?

 Not as far as I’m concerned 

you will need a structural engineer willing to sign off on it to design the lintels. 

What about foundation design, how heavy will it be. 

What about gable walls how will you cut them. 

 

 

[Declan52]

I think the issue might be proving that you can get them to sit tight together using some sort of adhesive that they form a water tight barrier. 

How do you work the peaks. That will be a lot of cutting to get your angle. 

Then how plumb will they actually sit. When you come to door and window openings your going to have a lot of cuts so it's getting all these and the full pieces below to sit plumb enough to be able to fit the doors and windows.

Then you have the actual openings. That's going to need a fairly big lintel which might put you out of coursing heights. You would just build a few bricks in normally and then build away. How do you do that. 

 

[PeterW]

22 minutes ago, K78 said:

icf is too much of a risk for me due to my site location. I’ve been on the durisol and isotex courses.  It would be hazardous and not worth the risk. I’m also not keen on some of the sketchier aspects such as how high you can go between pours. 

OK so reduce your risk. As long as the pour is continually reinforced to spec, there is little to go wrong if you’re pouring 3 blocks high at a time. That’s well within the scope of a self builder and a concrete pump isn’t expensive to hire. If you plan cleverly - such as looking at where door frames are etc to create a natural break in walls - then you could pour two sides of the house at differing times. One could be a “slow but steady” where the wall is near the road, and the other could be the less risky sides done in 2 or 3 bigger pours. 

 

7 hours ago, K78 said:

know for most they would be expensive and impractical. But labour costs for block laying I’ve had have been astronomical. This would be much cheaper for me personally as I could diy the construction with a mate and have the shell up in 2/3 days. 

 

I don’t think you’ll get it past a structural engineer or building control. There is nothing binding them together, no way of quality assuring or getting consistent results. I for one would not stand anywhere near a free standing wall of those at 300mm wide more than a metre or so high as they look dangerous. How would you do things like intermediate floors ..?? 
 

I also doubt you could lay 2-300 of those in 2 days even with a Telehandler as they are not something you can just slam into place - what are you going to do for any gaps for example...??

[PeterW]

15 minutes ago, K78 said:

Am I correct in assuming this would be classed as standard solid wall construction for BC and Mortgage?

No it’s non standard

 

7 hours ago, K78 said:

But labour costs for block laying I’ve had have been astronomical.

can you give an idea of costs quoted ..??

[K78]

 I agree ICF blocks are the best option for unskilled self builders to diy in 99.9999% of situations. But bursts are not uncommon on diy icf builds. They are not a huge issue in most cases (quick patch up and clean up).

 

As my site is elevated 2m above a footpath and road. It is not a safe option. A burst could injure someone or cause a road accident.

 

ICF also has some addition costs that lego does not. ( multi concrete pump hire and full scaffolding). The saving is obviously in lack of skilled labour and I really like the isotex blocks. With Lego, the labour and machinery hire is obviously more expensive, but they are safe for my site and go up quick.

 

Durisol (when in enquired over a year ago) officially said you can only go 3 blocks high so that is multiple pump hire too.

 

Isotex imo is a superior block and is stacked up to 2.25m with minimal bracing between pours. I’d like to use it but my site just is not suitable for a DIY icf block build. 
Im not even sure they would take the job on themselves as contractors.
 

insulation would be easily fixed to the concrete lego via mechanical fixings and brackets to hold the timber cladding over the insulation. 
 

I have good ground and would use strip foundations. It would be no where near as heavy as my retaining wall.

 

i wouldn’t have to cut anything for the gables. They make blocks shaped for that purpose. These blocks have moved on. 

 

If I had a less potentially hazardous site. I would definitely use isotex. 
 

 

Edited January 10, 2020 by K78

[K78]

23 minutes ago, PeterW said:

No it’s non standard

 

can you give an idea of costs quoted ..??

Thanks peter. That is the question I wanted a answer to.

80k labour to build a block house. 

 

I had quotes that high for my retaining wall. I built it for around £8-9k all in. 
 

The company who supplies the blocks are 5 mins away and I could have the walls stacked in 2/3 days. 

Edited January 7, 2020 by K78

[K78]

30 minutes ago, Declan52 said:

I think the issue might be proving that you can get them to sit tight together using some sort of adhesive that they form a water tight barrier. 

How do you work the peaks. That will be a lot of cutting to get your angle. 

Then how plumb will they actually sit. When you come to door and window openings your going to have a lot of cuts so it's getting all these and the full pieces below to sit plumb enough to be able to fit the doors and windows.

Then you have the actual openings. That's going to need a fairly big lintel which might put you out of coursing heights. You would just build a few bricks in normally and then build away. How do you do that. 

 

 Cutting isn’t a issue thankfully. They do gable blocks as many industrial/agri  buildings are built using them.

 

when on a flat foundation they sit prefectly plumb. They slot together like Lego.
 

My wall took a bit of extra work as the 3 bottom roes are 1.8m 1.5 tonne blocks laid length way to give depth to the base and the upper courses laid width ways and back filled with 20 tonnes of broken brick. All on a 10 degree incline foundation. Stacking a house with 300mm wide, 500 kg blocks would be easy by comparison. 

I was thinking of using the longer 1.8m blocks as lintel for smaller windows and doors, but my bigger windows will need a engineered solution I agree. 
 

I would think a waterroof barrier could be achieved using foam and quick set adhesive between the blocks, and pointing them externally and internally? 
 

 

[scottishjohn]

43 minutes ago, PeterW said:

icf is too much of a risk for me due to my site location. I’ve been on the durisol and isotex courses.  It would be hazardous and not worth the risk. I’m also not keen on some of the sketchier aspects such as how high you can go between pours. 

 

I certainly do not think that if built correctly and braced ,if poly type ,that there is any great risk for blow outs or collapse 

 

 my interest in these lego blocks  has been more in the way of thinking is there another way 

as for stability --use thin set mortar between them -then they are bonded 

IF it worked out cheaper  to use blocks then  concrete a ring beam  on top for to tie it  all together

floors -just fix wall plate to blockwork to sit joists onto 

using 300mm blocks makes cutting them to fit  realistic possiblity , but of course you would work it out as design stage to limit  the number of cuts

 door +window holes --steel liners 

as you have said what SE +BC would make of it is another thing 

[scottishjohn]

5 minutes ago, K78 said:

I would think a waterproof barrier could be achieved using foam and quick set adhesive between the blocks, and pointing them externally and internally? 

or just use stick on tanking as for basement- and as used in some sips roof systems,probably by the time you covered it in insulation  just a building wrap would be fine

[dpmiller]

80k *labour only* to throw up a few thousand block? Yikes. Where did they get that from?

[Patrick]

50 minutes ago, K78 said:

.

The company who supplies the blocks are 5 mins away and I could have the walls stacked in 2/3 days. 

 

Mystery solved. That's why in your case this might be a good idea. Transport is a massive issue nowadays. Stuff gets shipped across the world. That all costs.

If the company is local, this might as well be your cheapest option.

Used to be like this for all houses, people just used what s locally available. It just got a bit out of control over the last 50years (guilty as charged, I'm shipping all my material across Europe, but what can you do).

 

Only issue you might have is as @@PeterW

Mentioned:non standard construction.

 

[bassanclan]

It sounds like you should be contacting the manufacturer and speaking to some of the reps. They will know if there are any houses being built and what issues there might be.

[nod]

2 hours ago, Declan52 said:

I think the issue might be proving that you can get them to sit tight together using some sort of adhesive that they form a water tight barrier. 

How do you work the peaks. That will be a lot of cutting to get your angle. 

Then how plumb will they actually sit. When you come to door and window openings your going to have a lot of cuts so it's getting all these and the full pieces below to sit plumb enough to be able to fit the doors and windows.

Then you have the actual openings. That's going to need a fairly big lintel which might put you out of coursing heights. You would just build a few bricks in normally and then build away. How do you do that. 

 

There are plenty of ways to clad insulate All be it expensive ones 

My concern would be the foundation depths for such a heavy structure and widow and door openings 

I can’t see how this would work out cheaper than using concrete block and insulating 

At around 20m2

[K78]

12 hours ago, nod said:

There are plenty of ways to clad insulate All be it expensive ones 

My concern would be the foundation depths for such a heavy structure and widow and door openings 

I can’t see how this would work out cheaper than using concrete block and insulating 

At around 20m2

 
The foundation did concern me. But many solid walls are 225mm wide. Is 75mm such a big difference?

 

My ground is really good and I would use strip foundations.
 

The 1200 x 300 x 600 blocks weigh 518kg. Im guessing that 0.72m2 of 225mm solid block laid flat would weigh around a third less less?

 

With the various sizes and shapes available in the 300mm wide size i am thinking doors and windows won’t be a issue?

 

I know the owner of the company so I am going directly to him tomorrow. He will tell me one way or the other. 

 

 

 

[K78]

15 hours ago, scottishjohn said:

 

I certainly do not think that if built correctly and braced ,if poly type ,that there is any great risk for blow outs or collapse 

 

 my interest in these lego blocks  has been more in the way of thinking is there another way 

as for stability --use thin set mortar between them -then they are bonded 

IF it worked out cheaper  to use blocks then  concrete a ring beam  on top for to tie it  all together

floors -just fix wall plate to blockwork to sit joists onto 

using 300mm blocks makes cutting them to fit  realistic possiblity , but of course you would work it out as design stage to limit  the number of cuts

 door +window holes --steel liners 

as you have said what SE +BC would make of it is another thing 

I had a brief chat with a SE. He said there would be no issue at all. The structure would be stronger than a timber frame or cavity house. He raised cost as the main issue that concerned him as did every SE I mentioned using them for a retaining wall. 
 

If the blocks are sealed is there any difference between this a standard block construction as far as BC? The only difference is that the blocks are larger format. 

[K78]

15 hours ago, dpmiller said:

80k *labour only* to throw up a few thousand block? Yikes. Where did they get that from?

 It was a labour quote for  external walls, first floor joinery and roof structure.

 

Many say cavity walls with insulation is still the cheapest way to build. Maybe it is if you can lay blocks and do it yourself. Not a chance if you’re paying builders judging by my quotes. 

[dpmiller]

Have you any idea what portion of your £80k is actually for laying blocks? How any sqm is the house? What is the roof and FF construction?

[nod]

I think the only thing stop you could be cost That said I hope you do go ahead as it would be a really interesting project to see unfold 

 

As far as insulation I regularly use a external insulation- render system that would work well for you That would totally seal the building 

 

I will watch this thread with interest 

  Good luck 

 

[Gone West]

@K78 Looking at your pictures I can understand your concern about possible breakout with ICF and how you could install bracing to counter that. I like your idea of using the lego blocks and hope that you are able to complete your build using them. It's nice to see different construction techniques being used rather than the same old methods. Good luck with the project.