How do you dynabolt a metal frame to a concrete slab?

[Martinb]

I am by myself and for stability I have erected the frame by temporarily slotting the sleeves into each other and it is stable on a level slab, but now I have to dynabolt the frame to the slab. Maybe I have gone about this backwards could you please advise me on further directions.

 

[Noyade]

G'day Martin @Martinb 

I'm thinking the problem is you have the base perfectly positioned - but not enough room to drill the concrete with the traditional rotary hammer drill in the vertical position via the holes in the steel base?

Would something like the arrangement below assist in creating a "moon crater" in the concrete - so that you can move the frame later and drill with confidence? Of course you cannot use the hammer function in this scenario.

Just a thought.

Enough space for this?

Another thought.

Some angle-grinders with variable speed are provided with a chuck. More power in confined drilling.

Cheers!

[Martinb]

Hi Noyade, good idea did not know such a thing existed. The only other idea I had was to move the frame slightly to one side drill the holes then move it back, then onto the next one. When all the holes are done move it back into position and put in the dynabolts...what do you think?

[Noyade]

Afternoon Martin @Martinb 

What size are the holes in those steel footing plates? 10mm?

I think we would both agree that in a perfect situation we would use those pre-drilled holes as a template for the SDS bit. That way we could easily drill eight perfectly aligned holes. But there is no space for the rotary hammer drill in a vertical position.

So I was thinking we could at least drill say 5mm into the concrete with one of the methods above - move the frame to the side - and feel confident drilling with an upright rotary hammer drill to whatever depth you require, knowing that the drill tip will not wander with the initial impact.

Otherwise if you mark eight centres with pen or pencil - move the frame and then expect to be able to drill eight perfectly centred holes, is a tough ask - it certainly would be for me!

Or maybe at least - with your method - use a pointed cold chisel and try to hammer a small crater - dead centre in each hole, hopefully preventing the drill tip from wandering.

Whatever you do - I wish you luck and please let us know how you get on. 👍

[EricL]

Hello @Martinb 

Welcome to the Bunnings Workshop community. It's marvellous to have you join us, and thank you for sharing your question about Dynabolts.

It's great that you've received excellent advice from @Noyade. If you plan on moving the frame it's important to make sure that your mounting holes are in the correct position. I recommend putting the frame together first so that you get a true square finish. To give the frame a rigid stance, I suggest using ratchet straps to simulate the frame being screwed together.

Because you are very close to the edge of your concrete base, I recommend having a look at Ramset AnkaScrews and the Ramset Chemset systems. These mounting systems do not place any tension in the concrete and are therefore safe for edge or corner installations. Your shed frame looks very interesting, please make sure to post an update when you've completed your assembly. I'm sure our members will be keen to see what it looks like once you've installed the walls and roof.

Here is a handy guide to show you how the Ramset Chemset is installed: 

If you have any other questions we can help with, please let us know.

Eric

[Martinb]

Thank you Eric,

I think I would still try and use the dynabolts, what Noyade said seems to be a good idea but I will be off my feet for a couple of weeks due to a procedure in hospital. sos I will think about what you both have recommended as they both have merits.

Thank you gentlemen for you great ideas.

Regards

Martin 

[EricL]

Hello @Martinb 

Please take care and get well soon. Please let us know when you're ready to restart the project. We can pick up right where we left off. 

Eric

[Martinb]

Thank you Noyade for your advice. I am not sure if the frame is square, diagonally one is longer than the other but all of the girts are snug in their sleeves so there's no chance for corrective diagonal movement. Don't know what I have done wrong. any advice?

[Martinb]

Thank you Eric, I have measured diagonally and one is longer than the other even though the girts are snug in there sleeves. Don't know what I did wrong...any advice?

[MitchellMc]

Hi @Martinb,

Although you have the pieces snuggly fitted, there would still be a tolerance to the fittings. You might need a friend to assist, but I think you'll find there is still plenty of wiggle room to adjust the squareness of the frame. Grab yourself a rachet strap and place it between the uprights on the diagonal that is the longest. Crank down on the rachet strap to draw those corners together. Take regular measurements and stop when your diagonals are equal. Mark the Dynabolt locations with a felt-tipped marker, and then with your friend, drag the frame over 10cm so you can access the drill locations. Leave the rachet strap on whilst doing this otherwise the frame will spring back into the non-square position. Once you've drilled the holes, move the frame back and install the Dynabolts.

You'll find the frame is not square as when the spigots were welded on, they were likely a fraction of a millimetre off square, and this has then been exacerbated over the distance of the horizontal piece.

Be careful moving the frame, and take care not to injure yourself. Perhaps have a BBQ and invite some friends over to assist.

Please let me know if you have any questions.

Mitchell