Thanks @RejälRejäl said:
Do I understand correctly that the form is not attached to the rock except for the dowels that are cast over and the ties that go straight through (and in turn are held down by the reinforcement)?
How is the form sealed at the bottom?
What kind of tie is used?
Well, on the inside where the form is braced and the side that you start with, the 45x95 rule is attached to the rock to keep the form straight and stable when you start working.P pjop said:
We use expansion nails, 8/110/150mm.
I have tried concrete screws, but it's difficult to succeed with them in rock...
The reinforcement has nothing to do with the forming; it is placed when one side of the form is done.
We cut the boards to fit reasonably tight against the rock with about 1-2mm precision using a jigsaw.
Tie and washer as per the image, note that the ties are different for 12mm plywood and 21mm boards, and adjusted for the width of the casting; in our case, the wall in the image is 150mm thick finished concrete.
Sorry for the many questions, but is it a horizontal 45x95 that you attach with expansion nails to the rock, and then the vertical studs into it?Rejäl said:
Is no additional sealing needed if it's within those tolerances?Rejäl said:
Yes, just that, one more thing. In some sections, the new foundation wall will be cast outside an existing one. Is there any permanent stag that I can drill into the existing one, pull through the form and "nut" or weld to the outside of the form? Does it have to be stainless steel in that case?Rejäl said:
Either that or small stumps inside the laying rule that you also set the diagonal supports in, as I have inside in the pictures...P pjop said:
No, no more is needed, it's not leveling compound you're casting with...P pjop said:
Important to think about is the covering of 50mm around the reinforcement...
Then you can't use these braces; we usually go with threaded rods that are injected into the existing wall and then locked with a large washer and nut on the outside form...P pjop said:
You can put VP pipes around the threaded rods so that you can pull them out or cut them and repair the concrete holes afterward...
Awesome!Rejäl said:
If they are to be pulled out, how do I attach them best? Are expansion anchors the way to go, or are they too weak?
If they are to stay in place, do they need to be stainless steel since they won't be covered with 5 cm of concrete?
Of course, you can use drop-in anchors; we used anchor mass.P pjop said:
We drilled perhaps 80-100mm deep (depends on how deep your existing wall is) and then when we placed the threaded rods, we put them Max 50mm deep with the anchor mass.
Then when we removed the mold, we hammered the threaded rods so that they loosened, allowing us to pull them out.
It looks ugly to leave the threaded rods even if you go with stainless steel.
Got it.Rejäl said:
What do you do with the VP pipes when the threaded rod is removed? Do they become visible on the surface as rings and you just “concrete fill” the VP pipe holes?
One thing I can't see in your otherwise very good pictures is whether and how the boards are attached to the studs. Are they angle-screwed from the outside?
You remove them at least a few centimeters in before you concrete repair the hole.P pjop said:
Some board at the start needs to be attached to the horizontal 45x95, then we usually screw up board scraps on the outside with double drywall screws, probably works with chipboard screws too.P pjop said:
Then, occasionally, you need to attach the boards to the horizontal studs to keep them in place...