Levelling wooden floor

[RogerS]

I've moved along to the next room and have found a very thorny problem. The main beam (8" x 8" and 4m long) dips in the middle by about 20mm. This means that the upstairs floor is dished. Since I want to lay oak flooring up there etc I'd like to level out the floor to something approximating to level. The dip is just too noticeable to get away with.

The joints between joists and oak beam is as B in this thread . I originally thought that I could cut away the mortice in the main beam about 20mm vertically. That would let me lift the joist and I could pack it underneath with oak. However, the mortices are, very deep and go almost all the way through the main beam. So this approach will seriously compromise the strength of the main beam, I think.

So the only alternative that I can see is to plane the tops of the existing joists to an approximation of a straight edge. Then make 17 individually tapered pieces of green oak that will raise the floor level to the correct height. These would sit on top of the existing joists. Each tapered piece needs to be approx 20mm at one end and tapering down to 10mm at the other. Length is 2.3m. Bear in mind that these will all need to be tweaked. What's the best way to make these tapered pieces?

As an additional gotcha I'll need to somehow stain the green oak to approximate to the colour of the existing joists since our intention is to have these joists exposed downstairs.

As I write this I'm asking myself ...do the tapered pieces need to be green oak? Aesthetics say yes. Will the grain look radically different between the old and the new...even after staining?

Sorry to ramble on but I've been scratching my head for the best part of two days and discovered a whole new host of 'displacement activities' since I couldn't see how to resolve this problem.

 

[OLD]

Is it worth bothering with 20mm in 2300mm wont it just add to the old feel of the building .

 

[RogerS]

A good point and if you like walking "downhill" then "uphill" then I agree with you but if I don't get this level then when I come to lay the floorboards, build stud partitioning, fixing skirting boards etc, it will all need scribing to some degree or another. Hence my preference to get the floor level-ish to begin with.

 

[jasonB]

I'd rip the furrings out of air dried oak or any old beams that you have taken out.

You should be able to ping a chalk line onto the boards and then run them through a bandsaw, maybe tweak with an electric planner when fitted (drive the fixings down well!!)

Jason

 

[RogerS]

I'd rip the furrings out of air dried oak or any old beams that you have taken out.

I thought of that but am a bit worried about buried nails. My Lumberwizard goes into ecstasy everytime I bring it near any of the old stuff

 

[CHJ]

Don't worry about the furring showing, just use softwood.
I presume you are dry plastering/skimming between the beams, run 10 x 10 mm strips along each beam/furring against the underfloor as spacers, by the time this is done the furrings won't be visible and you will have a cavity for wiring.

 

[dirtydeeds]

i lived in some very old timber framed houses in suffolk when i was a kid and liked the feel of them and still do.

i also like feel of the changes made to timber framed buildings over the centuries

if i realy wanted a flat floor id go for jasons method its a modern version of an "honest" carpenters method but personally i wouldnt want to be too precious about perfect flatness.

i might think about (in a safe area) blow torching the firring pieces (assuming its oak) and wire brushing to remove the soft (burnt) grain giving an older texture

again personal preference i would darken the oak but make no attempt to match the colour

its also useful when it comes to modern day "structural surveys" most of them wouldnt know a real piece of wood if they knocked their head on it


my comments are all personal preference

 

[RogerS]

Thank chaps for the suggestions.

Jason - I thought about the bandsaw and it's a possible. I'd need to measure things up very carefully as I've not got one on site. Subsequent to this I did have a lightbulb moment and that is that, if I lower the supporting beam that the wall end of the joists sit on then I should be able to use non-tapered furring pieces which means I could use the table saw onsite. Needs investigation but a possibility....the bandsaw approach has merit...

especially as CHJ pointed out that if I'm going to stick plasterboard up underneath then it will hide the furrings and so I can use softwood which will be easier to work with....

Dirtydeeds - I like your ideas for ageing the oak and will give that a try.

 

[Mark.R]

I know the feeling of trying to achieve as close a result to perfection as I possibly could regarding my old Cornish cottage. We bought it ten years ago and was advised to knock it down and start from scratch, it was that bad. However we wanted to renovate and maintain the old theme throughout the project and plodded on to the end.

During this process I found it difficult to accept some of the blemishes in the original construction, but had to give in just now and again and work around them, although they sometimes showed.

My point is, that I felt I would never be able to get over living with the defects and would privately refer to them forever, which would irritate me.

I am glad to say, that I have learnt you have to draw a line on these defects (within reason obvioulsy!) and have learnt to live/put-up with them, and in fact feel they add to the character of the old property.

 

[kevinr]

No idea is this would work - but if you want to trim the furrings (mainly) in situ then could you:

1. glue the firring to the beam using clamps.
2. clamp a straight edged plank to each (or one) side of the beam.
3. use the edge to guide a power plane, saw or router giving you flat topped beam.

what ever method you use this might be a good way to do the final trimming if you want a really flat result.