dud parquet

[bitumen-coated]

I bought a 60sym load of dud parquet (only discovered in retrospect). It appears to be from at least 10 different batches. Thicknesses vary from ~7mm to 35mm (most either around 10 or 20mm). I need ~45sqm to be useable. Have scraped bitumen from edges of ~3000 blocks now, so thoroughly fed up and would welcome advice as to whether this is a no hope project. I can saw down some to approximately same thickness.
Questions:
1. what's the max height difference can be tolerated with different thickness of adhesive (intend using syntheprufe) and sanding?
2. if not removing skirting board, what's best to fill in equivalent of expansion strip?
Thanks

 

[WoodYouLike]

Hi bitumen-coated.

Adhesive isn't a leveling compound. The size of trowel used will 'dictate' the thickness of the adhesive, then you will press it down a bit by installing the blocks on to it, so using adhesive as leveler is not an option.
Have you also checked the width of the blocks? Differences in thickness can be sanded away (recommend you keep batches of same thickness together and gradually install blocks of lesser thickness next to each other; e.g. start with thickest in one area, say 35mm, next to that blocks of 30mm etc.)
If there are significant width differences your pattern, even brick pattern, will show gaps (which mostly can be filled, but makes installing a bit more difficult and frustrating).
To cover your expansion gap, you could use flat beading , nice neat finish also.

 

[bitumen-coated]

Thanks wyl.
I'm separating 3" blocks into 1/8" thicknesses eg 1-1 1/8" and 1 1/8"-1 1/4". Will 1/8" difference between blocks sand out or do I need to divide further?
Some of the blocks are 2 3/4" width, some 2 7/8" width, some 2 15/16". Will the latter two widths fit into a herringbone or does everything less than 3" have to be excluded from the pattern, other than for edging?

 

[WoodYouLike]

Sorry, we're 'metric' orientated I'm afraid. 1/8" makes 3.2 mm?
A proper sanding (starting with grit 40) take off appr. 1.5 - 2mm, so it's up to you to divede further or to sand more.
For a herringbone pattern every block has to be the same witdh, otherwise you're pattern will end up all over the place and creates gaps, wider gaps and huge gaps.
Sorry I have no better news for you

 

[bitumen-coated]

Thanks wyl
1. Does the expansion gap need to be symmetrical? I've a fireplace at one end of the room. Can I double up the expansion gap at the opposite end so the blocks are flush with the fireplace?
2. What's the benefit of cork expansion strips below any outside covering?
3. I've bought F21 styccobond. You seem to rcommend F92/93 (can't remember which). What's the disadvantage?
4. Is it better to have an oil-based or water-based filler? I'm unclear given different postings.
5. Although appears to be at least 10 different origins from the blocks I have, some from same origin (ie same varnishing) vary from 7mm to 25 mm. I appreciate that bitumen thickness has differed and that bitumen is not a leveling compound, but how much variation can I take up with diferent bitumen thickness ie can I alter by 2mm+?
Thanks for any advice

 

[WoodYouLike]

Thanks wyl
1. Does the expansion gap need to be symmetrical?

Yes.
To cover the expansion gap around your fire place you could install flat beading for a neat finish

2. What's the benefit of cork expansion strips below any outside covering?

None, cork does compress, but not completely and does fill the expansion gap, plus there is the risk of the cork getting very dirty and ruining the appearance of your floor.

3. I've bought F21 styccobond. You seem to rcommend F92/93 (can't remember which). What's the disadvantage?

Never worked with F21 (wood block - dipping grade) cause you'll have to dip the blocks in (and the only thing I can imagine is a lot of 'dripping') B92 is normal parquet adhesive to use with a notched trowel, B93 also, but is more flexible and mainly used with underfloor heating.

4. Is it better to have an oil-based or water-based filler? I'm unclear given different postings.

Water based is 'healthier', less VOC in it, oil or solvent/resin based has more VOC (Volatile Organic Compound) in it, but manufacturers are constantly reducing the levels and the product does work better. Water based products tend to 'slink' much more than the solvent based and take much longer to dry. We use Blanchon B61 resin filler

5. Although appears to be at least 10 different origins from the blocks I have, some from same origin (ie same varnishing) vary from 7mm to 25 mm. I appreciate that bitumen thickness has differed and that bitumen is not a leveling compound, but how much variation can I take up with diferent bitumen thickness ie can I alter by 2mm+?

The thickness of your adhesive depends on the type of notched trowel you use and adhesive isn't a leveling compound. Any height differences after installing will have to be sanded away.

Hope this helps

 

[bitumen-coated]

apologies for thick question, but...
If expansion gap for 4m wide room is 12 mm, is this split either side, or is it 12mm on both sides?

 

[WoodYouLike]

Thick questions don't exist Not asking a question when in doubt is thick
No, you calculate the width of a expansion gap, so 12mm on all sides.