New Joists for new 1st floor bathroom

[gs412m]

Hello,
I'm currently looking at relocating the ground floor bathroom to the 1st floor above the kitchen as I wish to convert the ground floor bathroom location to motorcycle storage/garage.
The room is 3000mm x 2200mm with 240mm masonary wall at one end and 140mm masonary at the other. To achieve more headroom for the bathroom upstairs and ensure it can support the weight of bathroom I am looking to reduce the ceiling height of kitchen as much as I can to approx 2100mm.  My first question and deciding factor for if this can be done by myself and least disruption is can this be achieved by using wall plates/ledgers secured to the walls using threaded bars epoxy resin into the masonary then new joists hung from timber joist hangers from these ?
reading the nhbc standards 2019 joist span tables i was looking at 75mm x 145mm C24 timber joists @400mm centres, but if any recomendations of joists less than 145mm suitable then that would be great.

 

Thank you in advance 

 

Graham

[gs412m]

.......I assume as per nhbc standards, masonary joist hangers are not permitted to be retro fit into masonary walls ?  or that would of been an alternative idea to drill out the mortar between the bricks where joists will locate, insert joist hanger then fill with mortar or epoxy resin ....   

[PeterW]

Afternoon. 

 

Wall plate resin bonded to the wall - not the plasterboard - is your way to go and will be fine. 47x122 would do it on the 2200 span assuming it’s actually 2100 when you’ve taken the wall plates off but tbh you will struggle to find it in a merchant and 6x2 is easier and probably just as cheap as it’s standard sized. 

 

What is the flooring going in the bathroom as if you’re going for tiles you could get away with using 18mm ply and glue and screw it to all of the joists and it will be bombproof. 

[gs412m]

Thanks for that, the joists will need to run along the 3000mm span, as across the 2200mm span at one side of it would be a party wall, so rather avoid that if I can.  I was looking at using M12 threaded bar (rawlplugs R-STUDS-12220-A4) inserted 100mm into the masonary at 400mm spacing (1 midway of each joist space either end) using their R-Kex II resin to bond these into the masonary ?

 

Hadn't thought of the flooring, was going to use carpet as current bathroom is, but 15 or 18mm plywood as the base ?

Edited May 19, 2019 by gs412m

[PeterW]

You can use pretty much anything to bond, I prefer the Fischer RCASV capsules and studs and you’ll only need a pack of 10. 

 

 

[Temp]

Personally I would try and build the floor strong enough and rigid enough for tiles if possible.

 

That might mean reducing the joist pitch  to avoid needing to double up the WPB?

 

I think 18mm is the minimum recommended (for carpet) but I might be wrong. 

[gs412m]

22 hours ago, Temp said:

................

That might mean reducing the joist pitch  to avoid needing to double up the WPB?

 

 

Thanks for the replies, just like to understand this part please

[PeterW]

1 hour ago, gs412m said:

 

Thanks for the replies, just like to understand this part please

 

Make the joists narrower as 18mm is “just” enough when you use it at 400mm centres. Go to 300mm and you will be fine. In your situation I think that only adds 2 joists so not a lot of extra cost. 

 

The big gain is glueing the floor to the joists with a D4 polyurethane glue which basically makes the whole floor and joist structure one solid piece. 

[gs412m]

Great, thank you both for the advice sounds a lot easier and quicker than chasing out the pockets for the new joists to fit into

[gs412m]

Just had a reply from Simpson Strong Tie as for suitable joist hanger which would provide the minimum solid joist timber bearing length of 75mm.  They pointed me in the direction of this product 

https://www.strongtie.co.uk/products/detail/face-fix-hangers/39

Looking at the installation images, I may not require the timber wall plate, as there are 4 x M12 bolt holes for fixing directly into masonry ??

Edited June 7, 2019 by gs412m

[gs412m]

so change of plan, the party wall is not an issue so it seems now. As the work would come under the Party Wall Act, so I would only have to give 2 months notice to neighbour before carrying out the work. This means I'll be spanning the joists across the shortest distance across the width of the room, meaning I can reduce the size of the timber to 38mm x 120mm according to NHBC Standards, but will still run them at 300mm centres just or extra strength as suggested.

3000mm  C24 38mmx120mm wall plate attached to the brick face with M12 threaded bolts 100mm deep, then the above joist hangers installed to give a 84mm bearing on the joist end.