Does the sill plate need to be anchored in the concrete slab, existing house

[mattiasohult]

I have a house where the sill was previously nailed to studs that were embedded in the concrete slab.

I have removed the embedded studs and thus the sill is not attached to anything. I have mounted boards on the wall.

Do I need to remove the boards and attach the sill, or can I leave the sill unanchored?

If the sill should be anchored, what is the best way to do it and how close together?

 

[-MH-]

Place one of these in each compartment. Pre-drill straight through the sill and concrete (assuming the sill is on concrete)

https://www.borco.se/product/expanderspik-80x70-fzb-25st

 

[Jansson69]

Put one of these in each slot. Pre-drill straight through the sill and concrete (assuming the sill is on concrete)

[link]

Absolutely a good choice, but the length of the expansion nail is too short if you're nailing a 45mm sill; you need at least 90mm in length, preferably 110 if you can drill that deep without risking anything in the concrete.

 

[mattiasohult]

Place one of these in each compartment. Pre-drill directly through the sill and concrete (assuming the sill is on concrete)

[link]

Previously it has been nailed approximately every 1.5m.

I have bought stainless concrete screws now that I plan to attach. According to the link

https://www.proffsmagasinet.se/bygg...ongskruv-utv-c3-1230-x-120-mm-25-pack-3009706

Considering that I have already attached boards to the outer wall, it feels a bit too much to put screws in every compartment... I'm thinking more like every 3 meters?

 

[Jansson69]

That screw should work but not every three meters, usually you nail/screw about c/c 600mm. You can probably bend the rules a bit, but three meters is too sparse...

 

[mattiasohult]

That screw should work but not every three meters, you typically nail/screw about c/c 600mm.
You can probably deviate a little from that, but three meters is too sparse.

Would this one that is 100mm work? Wouldn't you want something with a larger head?

https://www.proffsmagasinet.se/bygg...panderspik-borr-o6-mm-100-mm-100-pack-3053525

So you're suggesting to just take down all the drywall and OSB on the exterior wall then? :/

 

[-MH-]

Absolutely a good choice but the length of the expansion nail is too short if you're nailing a 45mm sill, it requires at least 90mm in length, preferably 110 if you can drill that deep without risking anything in the concrete...

Didn't check the length that carefully, you're right.

 

[Jansson69]

Would this one work which is 100mm? Wouldn't you want something with a larger head?

[link]


So you're saying it's just a matter of taking down all the drywall and OSB on the outer wall then? :/

It's a bit weak, better with 8mm in diameter as MH suggested above, yes 100mm in length is sufficient for a 45mm sill..
Yes unfortunately you need to anchor the walls better than every three meters, keep in mind that at doors it is especially important with good anchoring as these are slammed shut and thus create a nuisance for the wall..

 

[Hubbe73]

Another cheap option is a regular concrete anchor, then you can choose hot-dip galvanized, which will hold up without any issues. Stainless steel is overkill.

 

[Farstatjej90]

What is the purpose? So that the house doesn't blow away?🤔

 

[Jansson69]

Yes, a house is subjected to enormous lifting forces during wind, especially during stronger winds, but even lateral wind pressure could move the walls. The wall is also subjected to pressure at exterior doors, as these often slam shut, creating vibrations and pressure on the wall.

 

[roli]

What is the purpose? To prevent the house from being blown away?🤔

For example, so that the wall doesn't move when you slam the door as mentioned in a post a bit further up. Or that wind loads against the wall and roof cause the wall/house to move.

 

[vlindmark]

Cut openings in the wall panels 5x5cm or larger, at the bottom of the wall (easiest with a multi-tool) 60/100cm c/c distance, then you can mount angle brackets with screws into sylle/wall stud and then drill expanders into the concrete. The openings can then be patched up with plasterboard + filler or alternatively with a baseboard that covers.