Restoring wooden block flooring

[hudster]

Our new house has original wooden flooring throughout the ground floor but it all needs to be taken up, levelled and restored.

There are a couple of photos below. I would appreciate any advice with any of the following:

1 - Can anyone confirm what wood these are?

2 - Advice for levelling the floor - can I use a self levelling compound? A builder said I should use sheets of ply at different thicknesses but this sounds like a nightmare over such a large area with subtle differences in heights.

3 - Advice for removing bechamin, nails and sanding/sealing

Thanks in advance

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• hudster
• 5 Apr 2010
• 1

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• hudster
• 5 Apr 2010
• 1

 

[mac391]

1. Looks like oak but pics not brilliant. Clean a few with a damp cloth and retake pics whilst the blocks are still damp to be sure.

2. The expensive part!! Yes you can use a levelling compound but idealy you should remove all of the old bitumen adhesive from the concrete by shot blasting.
You might get away with scraping as much of the bitumen off as you can and only if there is a thin residue left you can screed over. Firstly using a neoprene primer on the bitumen then an acrylic levelling screed such as f-ball, stopgap 900 dpm prep, www.f-ball.co.uk

You then need to apply a DPM (damp proof membrane) such as F-ball F75 or F76 (see website) then use F-ball B93 adhesive, specifically dsigned to fix wood block to your DPM. If you don't use this adhesive then you have to apply another screed over the DPM for another type of adhesive to work.

If your still keen about doing it ?........

3. The time consuming part,, To remove the bitumen a table mounted belt sander with lots of coarse paper and a month of sundays!! For the nails, a hammer, pliers or whatever else works.

For sanding and finishing. Depends on the pattern you use. Once decided, keep the fine sanding dust and mix with lecol to use as a filler for the inevitable gaps you will have. Finish with varnish or oil. Something like osmo hardwax oil would be good.

good luck

 

[WoodYouLike]

As Mac says: it could be any wood-species, from Oak to Pitch pine or even tropical. They are just to "dirty" to tell from this distance
If it should be a tropical species you're better off with a deep seal oil followed by a wax-polish as wear and tear layer than the tow-in-one product HardWaxOil.
Difference between HardWaxOil and Oil and Wax

Another trick to help you remove the bitumen is to put them in a freezer so the bitumen becomes even more brittle. Then chisel most of it off before using sand paper - loads of sand paper (it'll clog up very quickly once the bitumen gets warmer through friction). The more you can get off, the better the modern adhesive will bond with it.

Follow Mack's advice on leveling compound and stay away from latex screeds!

 

[hudster]

Thanks for the useful replies, I have been down to a local flooring shop who are listed as suppliers of f-ball and they have gone away to price up the items mentioned above - what sort of price range should I be looking at?

I have cleaned up a block using a paint scraper and attached below - grateful for any ideas as to what this might be

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• hudster
• 7 Apr 2010
• 1

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• hudster
• 7 Apr 2010
• 1

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• hudster
• 7 Apr 2010
• 1

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• hudster
• 7 Apr 2010
• 1

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• hudster
• 7 Apr 2010
• 1

 

[mack4]

First off can I say your floor probably doesn't need levelled unless you've had recent work done on the subfloor.It looks as if the old 'bitumen & oil' adhesive has perished.So 'priming' the subfloor with some advice from F.Ball adhesives,might make screeding uneccessary.

F.Ball also make a bitumen based adhesive (15g tub/£29.50) which would probably suit your purpose, best speaking to their technical dept.I would also say that since the floor has been down for some time there's no need for another DPC as it most likely has one.As for cleaning the bitumen off the back of the blocks, no easy ways I know of,other than "getting on with it"

Finally I can see nothing a where a 'good' sanding won't clean & flatten the floor surface should you decide to go ahead and relay it.
Good luck,
mack

 

[hudster]

Hi Mack,

Yes in most rooms the floor is level so I was hoping I could just sand those areas without lifting the blocks.

In the dining room, the whole room slopes about 2cm down one side which needs to be sorted out as the kitchen floor next to it is level so it looks odd. It's just this room that I think needs to be completely lifted and sorted.

Any idea on the wood type?

 

[mack4]

It's a guess, but I would say "pitch pine" though it could be Oregon pine (Douglas Fir) which is quite resinous ,and smells really sweet when sanding.I'm sure some people won't agree however.They both sand up lovely!
P.S.If you do relay don't change the pattern, or you'll maybe find yourself short of material, and it'll be hard to source.
mack

 

[mac391]

Yes it does look like pine.. If it's confirmed i would be tempted to replace it with oak or another hardwood parquet around £25 per/m2 new. You wouldn't need to remove the bitumen and would probably sell th pine.

On the sub-floor, the old bitumen has perished but probably as a result of moisture over time. it's highly unlikely that your sub-floor has a DPM. From the first pic posted, the sub-floor doesn't look anywhere near good enough to lay a new floor!! And f-ball don't do a primer that seals bitumen.

On the plus side the remaining bitumen on the sub-floor should come up easy. For me, the only way to do this is primer, DPM, screed, B93 if you want it to last.

 

[mack4]

Wood block flooring used to be stuck down with a mixture of hot pitch (bitumen) and oil.The reason the flooring is loose, is because the oil has dried out leaving the pitch brittle.If there was any moisture it would have shown long before now.Wood block floors were never laid on floors without a DPM, it's unheard of! The old bitumen should scrape off the subfloor without too much effort, and the back of the blocks for that matter.The only problem is the "boredom" factor of cleaning them.I wouldn't replace them with "new", sanded up they'll look just fine. Besides you have them elsewhere anyway.
mack

 

[hudster]

The area where the blocks are loose in the photos is an area I believe has been flooded in the past as there was water damage to the wall and bay window ceiling. This may have been years ago as everything is bone dry now.

In all the other areas, the blocks remain stuck firmly in place so I think the flood water may be the only reason these blocks came loose - so it seems likely (and I hope) it is all covered by an existing DPM

 

[mac391]

Wood block flooring used to be stuck down with a mixture of hot pitch (bitumen) and oil.The reason the flooring is loose, is because the oil has dried out leaving the pitch brittle.If there was any moisture it would have shown long before now.Wood block floors were never laid on floors without a DPM, it's unheard of! The old bitumen should scrape off the subfloor without too much effort, and the back of the blocks for that matter.The only problem is the "boredom" factor of cleaning them.I wouldn't replace them with "new", sanded up they'll look just fine. Besides you have them elsewhere anyway.
mack

Your so sure this sub-floor has a DPM, where exactly is it ? under the concrete or under the floorboards ?
In the days when bitumen was used, the bitumen was the only DPM.

 

[mac391]

Hudster,

I know you would like to do this and keep costs down but if you were to ask me as a flooring contractor (25yrs) to re-lay your blocks, the first thing i would do is check your sub-floor for moisture.

This is industry standard and part of British Standards 8201 code of practise.!!

Your sub-floor might look (bone dry) as you say but the only way to know is to test it and the only way to test it is with a hygrometer. (not a moistuer metre from hss !!) which is a 48/72 hour test. If your sub-floor has a moisture content of less than 75% relative humidity, it is safe to lay your blocks, if it is more than 75% then you need a DPM !!!!!!!!

There simply is no other way to tell.

Mack4 insists wood block floors were never laid without a DPM ?? of course they were,, wood block flooing has been laid without dpm's for hundreds of years but in those days timber was dried out more naturally (without kilns) and were never dried to a moisture content of 8 -12% like they are today, thus they were far more stable.

He is also getting confused with a DPM (visqueen, or plastic sheet) that is installed under a concrete slab. The building industry only started using this method widely in the 70's/80's. Even if your sub-floor does have one of these there is no guarantee it is still working and if your house is pre-70's it won't have one at all, or you are very lucky... just chop a piece of concrete out and have a look.

By all means, if you want to reduce your costs then go ahead, but you shouldn't be installing a new floor on assumptions.

Don't just take my word for it try this, look for "site conditions" at www.englishtimbers.co.uk or google "wood blocks over concrete"

 

[WoodYouLike]

He is also getting confused with a DPM (visqueen, or plastic sheet) that is installed under a concrete slab. The building industry only started using this method widely in the 70's/80's. Even if your sub-floor does have one of these there is no guarantee it is still working and if your house is pre-70's it won't have one at all, or you are very lucky... just chop a piece of concrete out and have a look.

Hence why they used the old bitumen to glue down wood in old houses - acted a bit like a dpm, plus the tine gaps between the wood blocks allowed evaporation of any moist. Modern methods (building methods) and modern regulations (moist and sound control, plus VOC regulations) forbid the use of Bitumen inside the home now (thanks heaven for that!).

By all means, if you want to reduce your costs then go ahead, but you shouldn't be installing a new floor on assumptions.

We seem to agree on something

 

[mac391]

He is also getting confused with a DPM (visqueen, or plastic sheet) that is installed under a concrete slab. The building industry only started using this method widely in the 70's/80's. Even if your sub-floor does have one of these there is no guarantee it is still working and if your house is pre-70's it won't have one at all, or you are very lucky... just chop a piece of concrete out and have a look.

Hence why they used the old bitumen to glue down wood in old houses - acted a bit like a dpm, plus the tine gaps between the wood blocks allowed evaporation of any moist. Modern methods (building methods) and modern regulations (moist and sound control, plus VOC regulations) forbid the use of Bitumen inside the home now (thanks heaven for that!).

By all means, if you want to reduce your costs then go ahead, but you shouldn't be installing a new floor on assumptions.

We seem to agree on something

We do indeedy lol, except moist has ure after it i.e (moisture) ure ure... as in midgeure ure ure !!

 

[WoodYouLike]

Just blame that on my double Dutch English