Better odds with 11 model with 1/3 more dense blocks?

[Banff Martin]

Happy -30C! May your igloos be immortal!

I've read that the 11' model is challenged by the extra mass on the 8" walls, and a dome isn't as geometrically strong as the arch of the 8/9' egg shaped ones.

As I've just figured out that using snow shoe packed piles vs. fresh snow yields blocks 1/3 more dense, I have to wonder if this would be enough to make for a 'good' 11'?

As soon as we've a forecast weekend morning that won't have too much of a cold start for volunteers, I'm clear to run a campus igloo building event, and it would be neat to go big!

Thanks!

[Igloo Ed]

I haven't built very many 11 footers but I'm sure the ones we did weren't the exact right shape due to inexperienced helpers.
The tool produces the correct shape if used right but if not it will sag and once it sags it's starts to buckle do to the ration of wall thickness to igloo diameter.
The density of the snow will make a big difference but there is a lot of pressure down through the walls in an eleven footer.

[Banff Martin]

I've only built one 11' unit, and it was cursed by very warm weather - didn't freeze overnight for the first few days. After that the geometry was ruined and its fate was inevitable. On top of that, the snow was fresh and less dense to accept the load well.

As I'm always the form packer and use the plywood base vs. stake-pivot, I'm confident there won't be notable build issues. I may pre-mark the wall base on the pad, and water it days prior & boot-pack for the most solid base possible.

Anything else you might consider to aid an 11'? A wind wall will be built to the West where the Chinooks may come in from, and I'll add a cold scarf to cover the bottom 2 levels to insulate & stabilize those blocks.

Thanks!

[Igloo Ed]

Adding water might work if you don't wash holes down through the snow by using to much water.
But, if you used to much and broke and repacked the base, it would then be much stronger.
Adding a layer of ice to the floor might help a bit.
The thickening of the wall should help a lot too.
To bad you don't have a slurpee machine.

[Banff Martin]

(responded last night but there was an error in the post going through)

Indeed, If I build the pad over two evenings I could mark where the wall would sit & water that circle, a couple inches beyond either side of the 8" width, boot-pack that, and add more snow to level. I don't think I'll ice the floor as it would make 'servicing' the floor more difficult if the igloo is well used; I like to be able to scrape off the top skin of snow when the floor gets dirty with my metal shovel.

Don't tempt me to make a slurpee machine Ed, such things aren't impossible to improvise! =)

Thanks!

[Igloo Ed]

Well, as long as you're having fun, eh.
What a mess working with slurpee material would be. Do carry on though.