Loft boarding- cross battens 2x4 vs 2x6

[RSV]

Hi all,

I am looking to board up the loft to a good standard ("proper" and all).

Everyone recommends - in order to hold the insulation to raise the floor before boarding.

And the best way is to do this is to screw cross-battens into the ceiling joists - (2" by 4" timber battens have been recommended).

I understand that the insulation shouldn't be squashed by the boarding or it will just carry moisture and not actually act to insulate the house.

The knauff insulation sitting on top of the joists are around ~170mm thickness(6+inches).
- So i was looking to use 2" by 6" timber as cross battens instead.

Questions
1. Will 2" x 6" timber be too heavy for cross battening the original ceiling joists.

My carpenter said 2" by 6" timber might be too heavy - My initial thought wouldn't you need at least this depth for a full loft conversion??
My original ceiling joists are 2" by 4" timbers, around 13inches apart.


2. If I use 2" x 6" timber
Can I screw directly vertical into the ceiling joists?
If so would these be the best screws?
https://www.screwfix.com/p/spax-yellox-pz-countersunk-woodscrews-6-x-180mm-100-pack/45097

Or would i need to use joist hangers or screw diagonally into the joists?


3. How far apart does each timber batten need to be.
I was thinking - one every strip of insulation roll (so arround 20" apart) - is this overkill?


The loft space is around 22 Foot X 13 Foot.
I plan to board 19 Foot X 11 Foot (leaving the sides to breath).


Any help would be greatly appreciated.
Raj

 

[Ian H]

In a loft conversion the 6x2’s would be hanging off a steel so not on the old ceiling as yours will be.

I’d screw in at and angle with a 75 or 100mm screw.

 

[RSV]

Hi thanks for the response Ian,

Ok I see. Cheers for that - I didn’t realise it would be hanging off of steel.

Does that mean 2x6 timbers would be ok to use or too heavy too screw into old ceiling joists?

 

[Ian H]

I don’t know. 6x2 isn’t so heavy but I guess it depends how well the existing stuff is supported. Are there and walls under it?

 

[RSV]

Cheers Ian

Yes there are walls for the bedrooms running across the ceiling below the loft.

 

[bobasd]

if youve got lots of cablesrunning or lots of pipe runs then stop an get a joiner to come an have a look.


new loft joists dont touch the old loft joists.
use larger section joists eg 2"x6"/8" keep them seperate from the old joists an supported on wall plates an interior walls.
the insulation is irrelivent until joist work is done.

if you introduce steel you might as well do a loft conversion.

OP,thers a lot more details to this kind of job than you seem to think.

 

[Leofric]

What will the joists be spanning and what will they be built off ?