Floor chipboard - Joist up along the walls?

carl-johan · 7 Aug 2011 at 9:23 PM

Hello!
I am planning to lay down floorboards in a room and am considering buying Combinett from Swedspan: http://www.se.swedspan.com/website1/1.0.1.0/15/1/

When I read the installation instructions, it seems like you need to have joists along all four walls. Is that the case? :O

I am missing the joists (is that what they're called?) that are marked in red in this image:

Are these really necessary? Spontaneously, it feels like I have misunderstood... Why would they be needed? Isn't it enough with the regular floor beams, which are spaced 60 cm apart?

If they are necessary, how do I install them? A joist hanger takes up space sideways and it seems impossible to place it so that the beam runs parallel to the outer wall. Now I'm just confused...

How have you handled this?

Thanks in advance.

Best regards,
Carl-Johan

andersmc · 7 Aug 2011 at 9:32 PM

You should have support on all sides, otherwise, there is a risk that the floor will spring down around the edges when it is loaded. You can attach kortlingar that you have drawn, e.g., by toenailing them in place.

injonil · 7 Aug 2011 at 9:32 PM

Yes, they are needed. Skew nail/screw or attach small angle brackets with anchor nails/screws.

carl-johan · 7 Aug 2011 at 9:43 PM

Thank you for the answers.

But I can only toe nail/screw from one side on the noggings that will be against the outer wall. The outer wall is kind of in the way. Isn't it common to toe nail from two sides?

injonil · 7 Aug 2011 at 9:45 PM

You do not need to have the same dimension for the noggins as the floor joists.

carl-johan · 8 Aug 2011 at 10:54 AM

The floor joists are about 70x195 mm. What is an appropriate dimension for noggins?

But I'm still not sure how to fasten the noggins. Don't you have to toe-nail from two sides? That's not possible when the outer and inner walls are in the way. Or can I toe-nail from just one side? Will it hold?

FredrikR · 8 Aug 2011 at 10:56 AM

Skew nailing is when you nail at a 45-degree angle (towards the corner).

Daniel78 · 8 Aug 2011 at 11:30 AM

There are internal joist hangers that are convenient to use on such occasions, e.g.:
http://www.biltema.se/sv/Bygg/Monteringsdetaljer/Stolpsko/Balksko-invandig/

carl-johan · 8 Aug 2011 at 12:32 PM

Internal beam shoes! There you go! I knew there was something that solved the problem!

Thanks for the help, everyone.

FredrikR · 8 Aug 2011 at 12:56 PM

Aha, one of the salespeople at Hedins had no idea that it existed.

Then I've learned something new, again - thanks.

carl-johan · 8 Aug 2011 at 1:11 PM

A quick question: Is it enough if I screw the kortligen into the inner joist hanger from one side, or not? Otherwise, this idea falls apart because the outer wall is in the way.

hempularen · 8 Aug 2011 at 1:49 PM

It will be attached well to the chipboard with a number of screws; the board is also secured to the actual studs. The bridging really only needs to stay in place so it doesn't move before you get the screws in through the chipboard. Once it's attached to the board, it does its job of reinforcing the board.

injonil · 8 Aug 2011 at 2:42 PM

Well, then we probably need to use a bunch of extra screws. The type of screw and the number specified are not intended for these loads...

Daniel78 · 8 Aug 2011 at 3:08 PM

carl-johan said:
Just a control question: Is it enough that I screw in the short length in the internal joist hanger from one side, or? Otherwise, this idea falls apart since the outer wall is in the way.

As long as you adjust the joist hangers so that the beam bottoms in the joist hanger, there is no problem with just screwing from one side.

A tip is to install the joist hanger a bit too low, and then shim up with spacer washers like these:
http://www.haraldnyborg.se/merinfo.asp?varenr=4512&n=10

It usually goes easier and faster than kneeling and trying to get X number of joist hangers at the exact height.
Then start by driving an anchor screw through the underside of the joist hanger through the washers to ensure they cannot creep out in the future.

carl-johan · 8 Aug 2011 at 10:22 PM

You may not need to place the beam shoe and the nogging right next to the wall. If you position it a bit out, you can reach it with a screwdriver, and you aren't exactly jumping on the floor within the nearest 5-10 centimeters from the wall. Or am I thinking incorrectly?