Different flooring heights issue

[Selfbuildscott]

really appreciate some expertise on my flooring height issue. As you can see I’ve got the existing floor level, steel and new joists all at different levels. There is between 0-8mm from the joists to the steel and between 27-31mm between the steel and the final floor height.

I was thinking of screwing 5.5mm ply over the new joists to get me to the level of the steel and then using 22mm chipboard to get me to 27.5mm, roughly the height of the final floor. Does this sound accaeptable?

It’s a bedroom so underlay and carpet will help hide any slight changes in height. I had intended to use OSB3 T&G plywood flooring but this only comes in 18mm.

Im not certain about floating the chipboard over the steel though- any advice here?

Any advise gratefully appreciated

 

[conny]

I'm not a builder but I would be thinking of building up the new section level with the old and then infilling over the steel before boarding overto the final height.
Are you going to chipboard over the original floor?

 

[SFK]

You will feel differece even throgh carpet. So best to try an get levels as close as possible. Using 5.5mm of ply would make you have two very different heights at each end.

Use 2mm thick, 4cm wide wood strips from Wickes / B&Q / Homebase screwed on the the Joists hat go Left to Right in your images to make up the difference in height.
Do not put any strips on the joist that goes along the length of the I beam
More 2mm thicknesses where the difference is greatest.
Do same on steel I beam, but as at an angle make up square pads. Glue to steel with glue or no more nails.
Then put down floor board (ply better than chip) using screws.
SFK

 

[SFK]

UHHMMM Just did the maths, and

31+0= 31 - 22 = 9mm of spacer wood + 22mm floor board
27+8= 35 - 22 = 13mm of spacer wood + 22mm floor board
27+6= 33 - 22 = 11mm of spacer wood + 22mm floor board

If I got this right, I think I would consider thicker floor board, or starting with some thicker spacers.

 

[Doggit]

Sister 3x2s or 4x2s alongside the new joists to get them level above the height of the steel, and then use spacers to adjust the height of the other side.

 

[Selfbuildscott]

Cheers All

I’ve made a slight cock up with my measurements so ignore the 31mm part- this is 27mm, same as the rest of the existing floor height. (I was going off the old wall plate, which I still need to plane down).

Which leaves this:
27+0= 27 - 22= 5mm of spacer wood + 22mm floor board
27+8 = 35 - 22 = 13mm of spacer wood + 22mm floor board
27+6 = 33 - 22 = 11mm of spacer wood + 22mm floor board

Are you suggesting I cut strips of 5, 13, and 11mm ply and screw to the tip on the joists and lay 22mm floor over the top, not going over the steel.

As for the steel this can now be a strip of 5mm screwed to a strip of 22 flooring over the top, grab adhesive to the steel ?

 

[Selfbuildscott]

Sister 3x2s or 4x2s alongside the new joists to get them level above the height of the steel, and then use spacers to adjust the height of the other side.

Cheers I must admit I didn’t even think about sistering more timber. Would you notch out the timber to overhang the steel?

 

[SFK]

Self build,
I like the Doggits sistering method, but remembered I could not do this as had cable and pipes though my existing joists.

Which is why I used thin shims of wood like these on top of the joists
http://www.wickes.co.uk/Products/De...ings/Stripwood/c/1000207?q=:topSellers&text=#
Most of the DIY sheds have a selection of these in long trays at back of shop.

SFK

 

[Selfbuildscott]

Self build,
I like the Doggits sistering method, but remembered I could not do this as had cable and pipes though my existing joists.

Which is why I used thin shims of wood like these on top of the joists
http://www.wickes.co.uk/Products/De...ings/Stripwood/c/1000207?q=:topSellers&text=#
Most of the DIY sheds have a selection of these in long trays at back of shop.

SFK

pipe and cables are not a problem for me so I think I've found my solution. Although there are noggins already in place. Should I remove theese nogs and replace at the new level of leave them in and sister new timbers around them?

Do you know if 4x2 CLS is okay or does it have to be C16 rated framing timber for flooring?

Cheers

 

[SFK]

Self,
Keep in mind I am only a DIYer.

1) For increased fitting speed and the minimize hassle of lifting joists into your loft, I still like my method of shims of wood ontop of the original joists. But might be expensive. https://www.ebay.co.uk/itm/Hardwood...hash=item361511d618:m:m9sRHkX3PONUM-bipeLQn_w

2) I would be worried about removing noggins as they are keeping the original joists in place. And someone my have screwed the plasterboard below onto them so a lot of extra work to remove and shorten and replace.
Leave them and sister new joist around them.

3) I see C16 as being used where you want strength in the bending forces of the beam.
In your case you sister joists are simply transferring floor loading down into the existing Joists, there are not to strengthen the existing joists and so not relevant to bending forces. And the sistering will strengthen the existing beams a little anyway.
So I feel CLS will be fine.

4) I would try and notch out the timber to overhang the steel, and if any space (error in cutting) between the steel and timber, to make up the space either:
a) use a large blob of no more nails .
b) use some frame packers.
c) use a wood shim

SFK

 

[Selfbuildscott]

Self,
Keep in mind I am only a DIYer.

1) For increased fitting speed and the minimize hassle of lifting joists into your loft, I still like my method of shims of wood ontop of the original joists. But might be expensive. https://www.ebay.co.uk/itm/Hardwood...hash=item361511d618:m:m9sRHkX3PONUM-bipeLQn_w

2) I would be worried about removing noggins as they are keeping the original joists in place. And someone my have screwed the plasterboard below onto them so a lot of extra work to remove and shorten and replace.
Leave them and sister new joist around them.

3) I see C16 as being used where you want strength in the bending forces of the beam.
In your case you sister joists are simply transferring floor loading down into the existing Joists, there are not to strengthen the existing joists and so not relevant to bending forces. And the sistering will strengthen the existing beams a little anyway.
So I feel CLS will be fine.

4) I would try and notch out the timber to overhang the steel, and if any space (error in cutting) between the steel and timber, to make up the space either:
a) use a large blob of no more nails .
b) use some frame packers.
c) use a wood shim

SFK

isnt a professional just a DIYer with more experience anyway

I really appreciate your opinion SFK
I've got a few longish lengths of C16 4x2 and C24 5x2 (which I think might fit) anyway so might as well utilise these if I can. I've got the frame packers and no-more nails too.

to be bonest I didnt even know the stripwood existed - I thought I'd have to buy full 8x4' sheets and strip down myself so good to know its out there.

I'll try a demo with the sistering method and get back to you if I have any queries.

Cheers

Scott

 

[JohnD]

isnt a professional just a DIYer with more experience anyway

no, a professional is just a person who gets paid for doing it. He may be good, bad or indifferent. He may have more experience than a particular DIYer, or less.

A DIYer probably cares about his own home more than anyone else will.

 

[Doggit]

The problem with using fillets, is that unless you have access to a planer surfacer, then you'll seldom have the right thickness of fillet to use.

The C16 is fine to use, as there's no real structural strength involved. Leave the noggins in place, and notch over them, and the steel if possible, or work either side if the notch is going to virtually cut through the piece. Use screws long enough to go through both pieces in an up and down pattern, and spread a bit of glue in between them.

CLS is just a timber standard, and C24 has less knots and defects in it than C16, so it's the stronger of the two.