Browse Forums Renovation + Home Improvement 1 Jun 24, 2014 1:19 pm Hi, I'm looking to do two things and would love some advice. Our existing subfloor framing consists of bearers which are 100x75mm, joists are 100x50, with 1780 between bearers and 450 between joists. 1) I'm putting up some internal partitions. Single story, non load bearing and the roof is trussed. Where the partition wall runs parralel to the joists, can I just use MGP10 90x45mm to block between the nearest two joists for the wall? 2) We will be putting a bathroom in to an existing room where we'll be having a 150kg stone bath against the wall and wanted to know what we'd need to do to reinforce the floor as I don't want tiles cracking? We will be putting down 19mm scyon flooring. Will sistering the existing joists and bearers be enough? Thanks in advance Re: Subfloor joist blocking and sistering 2Jun 24, 2014 1:35 pm Quote: 1) I'm putting up some internal partitions. Single story, non load bearing and the roof is trussed. Where the partition wall runs parallel to the joists, can I just use MGP10 90x45mm to block between the nearest two joists for the wall? You need to consider how you will support the flooring. If using T&G floor boards you will need additional floor joists to support the ends of the floor boards. If using platform flooring (particle boards sheets) then the platform floor would go down first & non-load bearing walls on top. Additional joists would not be required except in the bathroom. Typically the bathroom floor should be fully supported on all sides and you may even consider if set-downs are required/desirable. Set downs may require completely reworking the bathroom sub-floor. Re: Subfloor joist blocking and sistering 3Jun 24, 2014 1:43 pm Thanks Betaloo. For the partition wall, I thought blocking at 450mm would be ok for the ends of the T&G board? I didn't want the floor to go under the wall. The reason for this is that I don't want to put the floor down in the bathroom until later so the plumbing is easier. Bathroom floor, as I assume it'll be easier to put in extra joists? Cheers Re: Subfloor joist blocking and sistering 4Jun 24, 2014 2:24 pm 1) Being part of the sub-floor framing, ordinary pine won't cut it . You'll need to use hardwood or treated pine.
2) That's a lot of extra weight. Throw in 200L of water and a person or two and suddenly the weight on that section of the floor is approaching half a tonne. I'd pour another pad and build a brick pier under the centre of the bath ( allowing room to connect the waste of course ) with another shorter bearer resting on it. Any flex in your floor may result in tiles popping or cracking as you've already noted. Quote: Typically the bathroom floor should be fully supported on all sides and you may even consider if set-downs are required/desirable. Set downs may require completely reworking the bathroom sub-floor. Did you get what Beetaloo means by set-downs ? Stewie Re: Subfloor joist blocking and sistering 5Jun 24, 2014 2:28 pm Thanks Stewie. 1) So 90x45 MGP10 H2 is ok for the blocking? 2) How about adding extra LVL 100x45 joists to the bathroom (so 200 centres) and just putting a pier under the bath? Cheers Alex Re: Subfloor joist blocking and sistering 6Jun 24, 2014 2:29 pm @Beetaloo this is what I'm thinking for the partition wall, as they'll be two different floors either side. http://www.renovate.org.nz/assets/Uploa ... g-3.17.jpg Re: Subfloor joist blocking and sistering 7Jun 24, 2014 2:33 pm That's fine but I'd give the distance between both joists a full 90mm with nogs. Otherwise when you screw or nail the floor down you will only have 20-25mm at the ends of the boards and you should have 10mm clearance for T & G boards to a wall to start with.
Whichever way you do it any extra support under the bath is better than nothing. Stewie Re: Subfloor joist blocking and sistering 9Jun 24, 2014 2:49 pm Quote: this is what I'm thinking for the partition wall, as they'll be two different floors either side. Looks fine to me. Refer to Stewie's response. Additional support for the bath is a good idea as green timber slowly shrinks and deflects under heavy load over time. If your sub-floor is less than say 1.5m above ground level, the timbers should be termite resistant (H3 or H4) or rot resistant hardwood. You may also need to consider termite barriers on the piers. If you do not want a step up into the bathroom, the subfloor in the bathroom will need to be lowered to allow for a screed & tiles. Check the installation manual for the scyon flooring to see if it requires additional support under joins in the sheets. I have a toilet that blocks up on the top (2nd) floor of a property. The toilets on the 1st and ground floor are OK) Blockage clears when the using a plunger. But… 0 500 DIY, Home Maintenance & Repair 3 pipes are coming from upstairs bathroom. 40mm from bathroom sink, 50mm from shower and another 50mm from the bathtub. Highly unlikely that any of these will be open at… 2 869 Seconded; we just used these last weekend to build a small deck. They worked perfectly as we have bluestone in the area where we wanted to build so digging down was not… 8 9084 |