Stickan56
Alternative construction to reduce the height of the concrete plinth and make it easier to cast.
Diagram of an alternative construction to reduce concrete plinth height, featuring a wooden post with screws and flat steel, highlighted measurements, and seals.

Stickan
 
  • Like
frihopper
  • Laddar…
Stickan56 Stickan56 said:
Alternative construction to reduce the height of the concrete pedestal and make it easier to cast.
[image]

Stickan
Thanks for the suggestion! But I don't quite understand, do you mean that I should replace the pedestal with a wooden post? So basically attach a post shoe/concrete pedestal to the rock and then a post on it? If so, I've considered it myself before because it seems super easy, but can the post handle the load?
 
R
As freehopper says, it is possible to perform in different ways. You need to make a concrete pillar on the rock that is at least 40 cm high and about 40x40 cm square, this is to ensure the anchor irons stand well on the rock. If you just use a sturdy post, it will hold, for example, by screwing together 3 pieces of 125x45 to make a post. The tricky part can be getting the anchors positioned correctly in terms of distance to attach the post, it usually ends up a bit crooked no matter what you do.
 
  • Like
frihopper
  • Laddar…
Stickan56
F frihopper said:
Thanks for the suggestion! But I don't quite understand, do you mean that I should replace the pier with a wooden pole? So essentially attach a post shoe/concrete pier to the rock and then a post on it? If so, I've considered it myself before because it seems very easy but can the post handle the load?
Just as "Rävlyan" writes, you should first cast a pier as the picture describes.

Stickan
 
  • Like
frihopper
  • Laddar…
R
R rävlyan said:
As frihopper says
There was a little mistake with the tipster :worried: it should be Stickan56 :) and not frihopper
 
  • Like
Stickan56 and 1 other
  • Laddar…
It certainly feels like a tempting proposal!

Could you use a post like this:
https://www.hornbach.se/shop/Stolpe...A-95x95x4200-mm/7189159/artikel-detaljer.html

Does the plinth need to be so large? A regular plinth is only 19 cm in diameter. With this volume, if I've calculated correctly, it will be about 64 liters of coarse concrete if it's 40 cm high and 40 * 40 cm in area. That's more concrete than a standard plinth at 19 cm by 140 cm (about 40-50 liters).
 
R
The post you are linking is somewhat like that, a pure post has the ability to twist and it cannot be stopped.
Therefore, screw a few together, a bit rough but it should stand against something on the underside as well.
As for the plint, it needs to be quite rough and tall, okay maybe 30x30 wide and the iron needs to be at least 20 cm high, so that the iron is seated properly, then some square reinforcement on the plint so it can't crack and a few extra dowels, it lies loose on the rock.
Concrete does not adhere to rock.
It's possible to make a sketch of it, otherwise in the style of what has previously emerged, with some modification.
 
  • Like
frihopper
  • Laddar…
R
It is possible to make do with plint and stolpe with a little ingenuity, how are the existing poles today, has the house sunk since you need to create new ones?
 
R rävlyan said:
The post you linked to is so-so, a plain post has the ability to twist, and it can't be stopped. Hence, screwing some together, a bit rough but it should stand against something underneath as well. As for the plinth, it needs to be quite coarse and tall, okay maybe 30x30 wide, and the irons need to be at least 20 cm high, for the irons to sit properly, then some reinforcement in a square on the plinth so it can't crack, plus some extra dowels, it lies loose on the rock. Concrete does not bond to rock. It's possible to make a sketch of it, otherwise, in the style of what has been discussed earlier, with some modification.
30 cm high * 30 cm * 30 cm sounds more feasible. The reason for hesitation is that this is the Stockholm archipelago, and it's a real hassle to haul stuff to the house which is in the middle of the island. Then it becomes 27 liters, about 2 bags of coarse concrete, which feels more OK. As long as it works structurally of course!

This is the construction I am thinking of:

Build a mold. Secure 3 pieces of 10 mm rebar into the rock with anchor compound 29 cm out of the plinth's 30 cm. Pour coarse concrete and then place 50 cm plinth iron which will then be 20 cm above the plinth surface. Screw together 3 pieces of pressure-treated 145*45 beams that I attach with hot-dip galvanized threaded rod M12 at two points according to Stickan's sketch. Then attach the 145*45 post to the house frame with angle brackets. Will it work?
 
R rävlyan said:
It is possible to make it work with base and post with a little cleverness. How are the existing posts today, has the house sunk since you need to make new ones?
It is addressed in another thread, https://www.byggahus.se/forum/threads/bjaelklagsregel-utanfoer-plintarna.291888/#post2668196, but it is probably about poor construction from the beginning, almost 40 years ago, as the outermost frame beam on the house is very close to the edge of the bases (which are straight) and on one base has completely "fallen" off.

Edit: different username then, which I lost the password to.
 
R
Will try to make a sketch for your work in the simplest way, is that OK
 
  • Like
frihopper
  • Laddar…
Stickan56
Last edited:
  • Like
rävlyan and 1 other
  • Laddar…
R
A simple sketch, hope you understand, a bit silly with text in paint but it works, hence a bit upside down on it.
 
  • A simple sketch showing a post attached to a beam with iron fittings and reinforcements in blue. Text annotations describe installation details.
  • Like
frihopper
  • Laddar…
R
Did not include, the post should go down to the casting with asphalt paper underneath, the wood will give a little over time and may sink a few mm, then it's good that it sticks to the concrete.
 
  • Like
frihopper
  • Laddar…
Thank you rävlyan, appreciate it VERY MUCH!
 
Vi vill skicka notiser för ämnen du bevakar och händelser som berör dig.