Flooring and doorways
Table of Contents
Flooring and Doorway Openings
New modern flooring will be laid, consisting of structural particleboard sheet subfloors with 14 mm solid overlay floorboards. The overlay board width will match the old boards but the species will be different. As far as I can determine the original flooring is Tallowwood, which has a Janka hardness rating of around 8.6. The new flooring will have a similar or higher rating.
1. The original main entrance door to the school residence revealed after cutting out the gyproc lining.
2. View from Bed2 with particle board cut and removed. There is no gyproc lining in Bed2. The builder autographed his work and gave the date as 26th June 1981
3. The closed-off doorway from the other side (Bed1) with the gyproc lining cut and removed. Again the builder dated the gyproc lining as March 1983
4. View from the original Main Bedroom through into the Parlour and fireplace.
5. The original main entrance to the school residence, open again for the first time in thirty five years showing the alignment of four doorways through the building.
The wear from foot traffic seen here on the limestone door sill will be retained
6. Floors removed and openings revealed
The gyproc lining is attached to furring battens. The horizontal battens supporting the bottom edge of the gyproc were nailed into the floorboards and those nails needed to be cut before the floorboards could be removed without damaging the gyproc. The new sub floor sheeting will slide under the horizontal battens far enough to provide support (with some packing) but still leave the required clearance between the sheets and the walls.
All joists appear to be in excellent condition and have been retained. Apart from the mandatory levelling of the joists the opportunity was taken to install underfloor insulation, which is R2.0 batts supported by plastic strapping stapled to the joists. The joists are unevenly spaced between roughly 300mm and 450mm and not necessarily parallel, adding some fiddliness to the work. Originally the joists were simply stood on their edges with no trimmers/noggins between them nor nailed to the bottom plates to prevent twisting or tripping.
7. Insulation installed and the first sub floor sheet down. I've decided to use Green Glue tape rather than construction glue between the original hardwood joists and the particleboard sheets. The sheets will be secured using screws rather than nails. The vent location has been marked on the walls to be cut once the overlay hardwood strips are down.
8. A stitched panoramic image, which makes straight lines look wonky. The sub floor in this room is now complete. The last row of sheeting at right fitted perfectly.
Floor revisited - after walls and ceiling demolished
I was never totally happy with this, my first ever, subfloor. It was a little springy and not perfectly flat. I felt I was walking downhill in places. I was learning and had reused the original joists without any additional work apart from leveling them as best I could. So I decided this was the time to fix it properly, i.e. while I'm reworking the whole room. I'd deliberately chosen not to glue the sheets to the joists, so that I could lift them again if necessary.
Because the screws had gone into old very hard timber not all of them came out easily. About ten screws had to have their heads ground out before I could lift the sheets.
9. Starting to remove the floor sheets.
Once the sheets, the insulation batts and supporting straps were gone and the trimmers were removed, the old joists could be moved aside. That was the time to rake and remove any debris that would make the already tight crawl space even more difficult to work in. All up about two average barrow loads was removed.
The new joists are 45x150x3600mm LVL, which on their own would be slightly undersized for the span but are more than adequate when sistered. Bolts and construction adhesive were used to bond the new and old joists together. Wherever the sag was small enough to allow it, the old joists were inverted before sistering (seen in images 10 without visible green tape).
10. Joists sistered, realigned and leveled.
I wanted to ensure I had at least one true 450mm c2c joist spacing each side of the duct so that I could accommodate a floor hatch, or possibly two if necessary. Because of the more or less fixed construction around the hearth every other spacing had to be less than 450mm, so I arranged those smaller spacings where I felt the additional stiffness would work best. The original joists where also not parallel, so I fixed this. The obvious exception is visible at centre of image 10a, where the new joist could not be sistered as usual if it was going to run parallel. I also arranged the joists to re-use most of the previous sheeting with minimal cutting, but I'll still need another 1200mm x 900mm sheet, which will cost around AU$25. I can't reuse the old green accoustic tape seen in image 10 so another roll was ordered. I need 1.5 rolls (45m) for this room. All up this reworking has cost a little over AU$500 for materials.
After levelling using the bedroom two floor as the reference through the connecting doorway the replaced sheets will be approximately 1cm higher than previously, which works a little better for the external door sill transition.
The electrical outlets and wiring will also be redone underfloor while the floor is up. This will eliminate all wiring runs above skirting level in this room, making it a little safer as well.
The ducting will be raised and suspended where it is parallel to the joists, particularly at the bottom of image 11a (top of image 10c), to allow air to flow more freely across the crawl-space.
The finished floor looks little different to the first version. Images 68 show the finished subfloor with two hatches and the odd coloured extra piece that I needed after trimming some pieces (the original piece from that corner was just too short to fit the realigned joists). It appears the supplier has changed their process as I couldn't get sheets of the same appearance. It doesn't matter because they'll be hidden.
Also shown is the ventilation register box poking through it's cutout. I've decided to do the cutouts now rather than wait until the overlay is down.
11. Subloor 2.0 completed
Then there is just the internal doorway landing to reconstruct. I'm replacing the original sill piece with a new one made from an original tallowood floorboard, not because the old one is well worn, which I would've preferred to keep, but because I want a wider board. It will sit directly on the 60mm wide LVL shown in images 12. The subfloor sheeting needs to sit on framing 12mm lower (sheet plus overlay plus glue less sill thicknesses = 19 + 14 + 1 - 22 = 12mm).
The 60x150mm LVL is an offcut from the new bedroom two joists and the framing is reused radiata pine from the demolished ceiling joists.
12. Internal doorway landing.