Solid wall block choice, Ytong, Celcon, Thermalite?

[Jeremy Harris]

IIRC, some ICF companies can supply curved forms, so that might be an easier way to get a well-insulated and relatively easy to build round house.  There was a Grand Designs episode years ago, with an ICF build that had a round, spiral, tower in one corner, to a pretty tight radius.

[K78]

On 08/07/2019 at 13:12, patp said:

Did you decide on Ytong blocks @romario. Jewsons are offering them to us at £11 per sq m as all others are out of stock.

 

 

On 08/07/2019 at 15:17, PeterW said:

 

Is that ex VAT or inc VAT..? I’m being quoted £9.20 by TP and £9.25 from MKM ex VAT currently. 

 

I cant find prices anywhere near these?

[Mr Punter]

On 11/07/2019 at 07:16, Russell griffiths said:

How are you going to get blocks to sit nicely in that radius. 

Would you not be better with a shorter block, brick so it follows the radius better, it will be awfully notchy otherwise and a major pain to fit your external insulation. 

  

Are you dead dead set on this method. 

 

On 11/07/2019 at 10:04, Declan52 said:

You have to cut each block in half to get a curve anywhere near decent. Which is very time consuming. Building a radius with blocks can't be done with a line so having to cut each block plus build free hand you will be paying a massive premium to build in that shape. 

Then as @Russell griffiths also says how are you going to bend enough insulation around that shape so you get it to passiv standards.

 

No so, you will easily get standard concrete blocks to go round with no problem and no need to cut the blocks. Given your diameter of 20m, the building circumference is 62.83m, so 279 blocks per course.  The difference between the inside and outside of each perp join will be about 2mm and the maximum deviation in render thickness will be about 1mm.

 

 

[Russell griffiths]

Cool, nicely worked out, I thought it would be far tighter than that. 

[scottishjohn]

On 11/07/2019 at 10:10, JSHarris said:

IIRC, some ICF companies can supply curved forms, so that might be an easier way to get a well-insulated and relatively easy to build round house.  There was a Grand Designs episode years ago, with an ICF build that had a round, spiral, tower in one corner, to a pretty tight radius.

Isodom2000  system has curved sections avaialble

 

https://econekt.co.uk/wp-content/uploads/2016/02/ECONEKT.-ICF-Elements-Brochure2.pdf

made to whatever thickness and curvature you want

 

Edited July 15, 2019 by scottishjohn

[Declan52]

3 hours ago, Mr Punter said:

 

 

No so, you will easily get standard concrete blocks to go round with no problem and no need to cut the blocks. Given your diameter of 20m, the building circumference is 62.83m, so 279 blocks per course.  The difference between the inside and outside of each perp join will be about 2mm and the maximum deviation in render thickness will be about 1mm.

 

 

That's a tidy bit of working out alright. It's still going to be free hand though which will take a fair bit of time to set out for a start then doing the actual building of the blocks.

[Jeremy Harris]

Just a slightly wacky thought, but I wonder if it would be possible to set up a dead vertical scaffold pole in the centre, firmly set down into the ground so it can't move, and then have a 10m long arm that pivots from that to provide a reference to help keep the blocks following the curve?

 

Some sort of adjustable stand might be needed to hold the arm at the right level for each course, but I doubt it'd take more time to set something like this up than it would to set up a line several times on a conventional build.

[Brickie]

8 hours ago, JSHarris said:

Just a slightly wacky thought, but I wonder if it would be possible to set up a dead vertical scaffold pole in the centre, firmly set down into the ground so it can't move, and then have a 10m long arm that pivots from that to provide a reference to help keep the blocks following the curve?

 

Some sort of adjustable stand might be needed to hold the arm at the right level for each course, but I doubt it'd take more time to set something like this up than it would to set up a line several times on a conventional build.

Hard core game of swing ball you’re proposing there, @JSHarris :))

Not that wacky Id say-I’ve never built a twisted pier but I believe a micro version of what you suggest is one method of building them. 

Another method might be to keep your centre point as a reference check,set up vertical profiles at say,4 metre intervals & make a curved profile to the shape of the circumference. It’s probably too impractical & time consuming to check every course but you could check maybe every 4th & correct any minor deviations so they don’t increase. 

Btw,my experience of building curved brickwork (albeit garden walls,so more forgiving of minor inaccuracies) was that production can be surprisingly high. Yes,it’s all level work but that’s offset to an extent that you’re just working the length of your level for the height of the lift before moving along and repeating the process.

[Russell griffiths]

17 hours ago, Declan52 said:

That's a tidy bit of working out alright. It's still going to be free hand though which will take a fair bit of time to set out for a start then doing the actual building of the blocks.

When I did a bit of radius work, we used a timber former, if the former was cut from ply you would have a plumbing point every 2.4m you kept these plumb and used the former to tap the bricks from behind until they touched the former. 

 

I still think the brickies on this will be adding a fair margin of pain in the arse markup. 

[romario]

On 15/07/2019 at 13:51, JSHarris said:

Just a slightly wacky thought, but I wonder if it would be possible to set up a dead vertical scaffold pole in the centre, firmly set down into the ground so it can't move, and then have a 10m long arm that pivots from that to provide a reference to help keep the blocks following the curve?

 

Some sort of adjustable stand might be needed to hold the arm at the right level for each course, but I doubt it'd take more time to set something like this up than it would to set up a line several times on a conventional build.

We've been thinking the same way.

I exactly used scaffold pole in the centre

[romario]

On 11/07/2019 at 10:10, JSHarris said:

IIRC, some ICF companies can supply curved forms, so that might be an easier way to get a well-insulated and relatively easy to build round house.  There was a Grand Designs episode years ago, with an ICF build that had a round, spiral, tower in one corner, to a pretty tight radius.

Thanks for your comment.

I've been thinking about the ICF but there were couple reasons whey I decided on the solid block work with external insulation.

1. Being my first house build and roundhouse on top there was no way I could commit to fixed design at the beginning of the project.

I am a person that I can make better decision seeing the things in real than just on the drawing.

Right now I built up the walls up to the windows opening and I am still fine tuning the exact locations of the windows.

This wouldn't work if I went for a big contractor but because I am hands on I suppose I can be a bit more flexible.

 

2nd reason was that because the house had planing with external cladding anyway I preferred the idea of having the block work on the internal side and insulation on the external side (A bit of the european style:) ) 

 

3rd reason being already unique shape I wanted to keep it reasonably standard construction for mortgage purpose. I don't know if most lenders are ok with ICF.

 

 

However, when I was checking every block for the first few rows with a long timber stick sometimes I wished I went for ICF

 

[Mr Punter]

What a great location!

 

So it looks like you have gone for a mix of hollow and solid concrete blocks. Are you filling the hollows with concrete?

 

Jumping ahead a bit, what fixings are you looking at for the timber support battens through the insulation?

[romario]

50 minutes ago, Mr Punter said:

What a great location!

 

So it looks like you have gone for a mix of hollow and solid concrete blocks. Are you filling the hollows with concrete?

 

Jumping ahead a bit, what fixings are you looking at for the timber support battens through the insulation?

Below DPC structural engineer preferred concrete blocks.

I could either go for solid concrete or hollow concrete and fill them in with concrete.

As the wall thickness is 215mm solid concrete blocks would need to be laid flat as the largest size I could get in solid format was 140mm x 215 x 440

I understand this is due to the weight of the blocks.

I suppose the cost of laying solid blocks flat and so more courses comparing to hollow blocks and filling them in would be similar.

 

I decided on hollow because when filled in with concrete they are actually a lot stronger.

Also on South side there will be quite a few larger window openings so the hollow blocks when reinforced with steel bars and concrete can be used for columns.

You can see on the photo the metal bars going down right to the footing.

[Mr Punter]

Must have been a pain lifting the blocks over the rebar. How are you getting the concrete up to fill them? Will you wait until the wall is full height?

[romario]

1 hour ago, Mr Punter said:

Must have been a pain lifting the blocks over the rebar. How are you getting the concrete up to fill them? Will you wait until the wall is full height?

I suppose I had a choice to cut the 3m bar lengths to shorter lengths and overlap the rebars.

I left the 3m lengths and went for the standing platform to slide the block down but it is a 2 people job.

I've chosen the hard way but without cutting

 

I've been filling the hollow blocks every 4 courses as I am not sure if it would be a good idea to leave them free standing on its own.

I suppose they are not very strong without the rebar and infill.

 

 

[Mr Punter]

18 hours ago, romario said:

I've been filling the hollow blocks every 4 courses as I am not sure if it would be a good idea to leave them free standing on its own.

I suppose they are not very strong without the rebar and infill.

 

I think @AnonymousBosch would agree with you there.

 

Keep up the good work!