what base to use for dome?

[Nigella Bryant]

Hi all, about to press the order button on building itmes for the base of the pulsar dome. A question before I do. I'm going to put the dome on a wooden frame of 1500mm x 50mm timber. I've got a patio where it being positioned so I'm wondering to just lay the frame on top of that or first lay rows of building blocks cemented down with bolts which the frame would be bolted to. Don't really want to do a complete concrete base. So the question is first do block rows or jus to lay the frame on the current patio.

Many thanks Nigella.

 

[Swoop1]

How about a few of these  secured to the patio with no more nails?

[Nigella Bryant]

10 minutes ago, Swoop1 said:

How about a few of these  secured to the patio with no more nails?

Those look interesting Swoop1, I'll look into that. Save all the hard work, lol.

[Rusted]

I'd worry about the dome taking off in a gale unless more serious ground anchoring is also applied.
Like expansion bolts into concrete or "epoxy" chemical fixing of long, galvanized bolts.

For my 2 storey, octagonal, observatory building I used tapered,  buried concrete "carport" anchors/foundation blocks.
Once they were firmly backfilled with self compacting sand/gravel, the blocks would have to be lifted out of the ground.
Rather than "just" lying on top of it. No detectable movement yet despite some pretty severe gales.
 

[Nigella Bryant]

1 hour ago, Rusted said:

I'd worry about the dome taking off in a gale unless more serious ground anchoring is also applied.
Like expansion bolts into concrete or "epoxy" chemical fixing of long, galvanized bolts.

For my 2 storey, octagonal, observatory building I used tapered,  buried concrete "carport" anchors/foundation blocks.
Once they were firmly backfilled with self compacting sand/gravel, the blocks would have to be lifted out of the ground.
Rather than "just" lying on top of it. No detectable movement yet despite some pretty severe gales.
 

Hi, yeah, I agree, decided concrete blocks cemented down and rod bolts cemented into blocks and bolted in the wooden frame. All ordered now so I'll be posting about the start to finish of erecting the dome, lol. Work hopefully starting end of next week after delivery of all the building materials. Soryy if it'll be the end of the sunny weather then, lol. 

[Nigella Bryant]

Hi all, I'm going to start a new post on erecting and building the dome. Building materials are trickling in now and should have everything by end of next week. 

[Louis D]

To avoid your dome shifting between wet and dry seasons, I would want to get down below the top few feet of soil with concrete pillars unless you sit directly on bedrock.

[Nigella Bryant]

1 hour ago, Louis D said:

To avoid your dome shifting between wet and dry seasons, I would want to get down below the top few feet of soil with concrete pillars unless you sit directly on bedrock.

Hiya, yeah, bungalow is built on rock, had to be dug out as it was originally a steep slope I've been told. I've lifted some slabs and can't dig down more than about 50mm before hitting rock. 

Edited June 6, 2020 by Nigella Bryant

[Rusted]

1 minute ago, Nigella Bryant said:

Hiya, yeah, bungalow is built on rock, had to be dug out as it was originally a sleep slope I've been told. I've lifted some slabs and can't dig down more than about 50mm before hitting rock. 

In that case, forget everything I have said so far on buried concrete blocks.

Barring earthquakes of course.