IanWatson

Hello all,

I've just bought a flat over here in Amsterdam - needs a lot of work doing although it's structually sound and dry.

It has the original floorboards, but I am contractually bound to fit 30mm Fermacell soundproofing on top of these.

I was recommended and have bought 60 m2 of oak flooring - comes in 10 inch wide planks from 3 to 10 feet long, with well-fitting tongues and grooves machined in.

I was planning on laying it floating with an expansion gap as advised by the flooring wholesaler - the rooms are around 4m by 5m . The boards will have had three weeks to get 'used' to the humidty levels in the flat.

All was going well until I got a guy round to quote for plastering the walls - he's a Brit running a building company in Amsterdam. He took one look at the oak boards and the soundproofing and basically said 'you can't lay hardwood floors floating - they have to be secret nailed. You can't nail flooring directly to the sound proofing so you'll need to put down 18mm thick wood underlay, then lay some wooden 'lats' (sp?) on that, to which the boards are then nailed to'

So my nice 'simple to fit' floor could turn into a hugely expensive job, not to mention losing about a foot of headroom in the flat

Phew - sorry about the essay! My main questions are..

1 - can hard wood floors be laid floating without major problems?
2 - if so, what are the limits of width and length?
3 - if I have to lay it 'secret nailed' can I nail the flooring to
itself but glue it to the underlayer?
4 - anyone got any experience with Fermacell Estrich sound insulation?

thanks in advance
ian



[Edited by IanWatson - 5/23/2002 4:16:39 PM]

jjones

fit it floating - do not use ferm a wotty insulation - just claim its done - whose gonna check it any how

AlexM

Hi,

It wasn't clear if your hardwood flooring is laminated or solid. If it is laminated (4/5mm hardwood cap with ply or blockboard substrate) then I can tell you that I've had this down in an area approximately 11m x 5m without any problems for two years.

This is a 'floating' installation on acoustic underlay.

Not sure if solid wood floors need to be treated differently though. If in doubt, refer to the manufacturers for their advice.

Cheers,

Alex

IanWatson

Thanks for the quick replies guys..

The lady who lives in the flat below is OBSESSED with the noise issue. I've not even moved in yet and she's already spoken to me a number of times. I normally just ignore batty 'older' people, but her brother owns a law firm...

The flooring is basically 5/8 inch thick solid wood planks, with tongue-and-groove machined on the edges.

fast bloke

It will more than likely warp if you lay it floating. The job described above should not be that expensive. You put down the underlay, then 18 mm ply (costs about 3 quid for an 8*4 sheet, so less than 100 quid all in) and then the lath on top, again, minimal cost compared to the floor and soundproofing material. If you can use a saw you could do this yourself in under a day. Secret nailing is just nailing at an angle through the tounge so that you cant see it when you put the next board in place. An alternative would be to lay 38mm joists at 400mm centres, then lay the soundproofing between these and fix the floor to the top. Should be cheaper, you will lose less headroom, but your joinery skills need to be a bit better to get them all dead level

carl

The second option would appear to offer more scope for noise. In the first solution, the wooden flooring is decoupled from the real floor by the soundproofing material. In the second solution, the 38mm joists couple the wooden flooring to the real floor, so it will be possible for vibration to be transmitted through these.

fast bloke

Alternatively - replace the batteries in her hearing aid with duff ones

CArl is right about the noise though. If she is really pushing it she will still hear you walking about.

[Edited by fast bloke - 5/23/2002 4:46:19 PM]

IanWatson

Aaarrghh - this isn't helping much - this thread sounds like my own internal dialogue.

Good reply Fastbloke - I guess it might be time to use all those Metabo tools I persuaded my better half that I would need to buy!

Although I would prefer someone to post a reply that totally and factually contradicts the Ulsterman!

One extra question - when I spoke to my 'advisor' he initially suggested putting the laths down. When I spoke yesterday he didn't mention those, and indicated I should nail the boards together and glue straight to the ply.. Would this work?



Go on - somebody save me some work..

[Edited by IanWatson - 5/23/2002 5:09:22 PM]

fast bloke

Erm - you should glue the boards together and nail them to the ply. It will be incredibly difficult to do it the the other way. No reason why this wouldn't work, but some 'natural' wood floors need ventilation below. If you are buying the stuff new there should be guidance about what you can lay it on. There 'wood' be no problem doing this with a laminate floor.

p.s. - I am not a qualified expert, but I've wooden floored the entire house, so I have learned a lot from my mistakes If your mate is a decent builder you will probably be OK following his advice. Especially if he can't make money from it

IanWatson

cheers - that's what I meant (gluing etc), Fast Bloke!

This bloke (deffo not a mate!) was originally suggesting some laths between underfloor and boards.

When I bought the boards I was assured by the guys at the warehouse that floating was the way to go - I wouldn't have bothered otherwise as my place will be rented out after a year or so, and although it doesn't seem a tricky job to lay it fixed, I'm a little short of time!

Channeling all the electrics into the wall is top of the list right now.


I hadn't met the geezer who gave me the fixed-floor advice until he came round to quote for my plaster work - he's deffo angling for the business. Which isn't a reason to discount his comments entirely, but I'm a cynical barsteward

Chris T

ok I laid a floating floor in my place too.

just a roll of sound proofing then tongue and groove on top
I 'fixed' it around the edge using quarter beading to hold it in place/stop it warping.

DON'T glue it to the plywood - its a nightmare. - you are not going to be in the flat - go for the quick and easy solution.

in my opinion.

Olly

Never glue t&g timber boards together. This will guarantee that the boards will split as drying out (and therefore shrinkage) takes place. The expansion/contraction takes place at the tongue and groove joint, leaving the board itself intact. The wider the board, the bigger the problem. 3 weeks to acclimatise is wise, although still accept that shrinkage will take place.

10" wide solid oak boards are VERY wide, and great care will need to be taken to avoid cupping. 5" is the norm, and 4" is preferable. An air gap will be required underneath the board to prevent sweating underneath, and ensure the board reacts to humidity changes as equally as possible.

For the best results and the least amount of work, fix 2" square softwood battens along the line of the existing joists, screwed to the original floorboards (make sure the screws will NOT protrude through the boards to avoid any floods). Lay the insulation between the battens, and then nail the oak boards across battens. Secret nailing is preferable for cosmetics, always nail through the tongue side at 45 degrees.

All assuming that this is acceptable as per the insulation manufacturers instructions.

Olly

Nice double post.



[Edited by Olly - 5/23/2002 6:53:54 PM]

mattstant

take ollys advice
cabinet makers have to know a heck of alot about wood and dont mess with big bits of hardwood
most people are talking about laminates which are a totally different animal

jjones

buy some axminster - the old bag will never hear you though that.

IanWatson

cheers Olly - after sleeping on the advice I think I'm going to bite the bullet.
One quick point - the boards are only 5 inches wide not 10 (my brain is becoming addled by the metric system), although I don't think this really changes the situation.

So..

I plan to put the insulation on top of the existing floorboards, lay 18mm 'underfloor' tongue and groove ply boards which I hope(if glued together) will give me a static surface to which I can secret-nail the boards.

Just a few more questions
Should I glue the underlay ply to the acoustic flooring?
I'm planning on nailing every 15 cm - is that excessive?
What's the longest length of floor I can get away with if nailed (longest length could be 12 metres, maximum width will be 5 meters)


big thanks
Ian

Olly

Ian,

There is nothing wrong with the method you intend to use. You can either lay the floor this way, or insulate between fixed battens as I described.

There are pros and cons with either method. Assuming that this is OK as per the insulation manufacturers instructions, if you batten the floor, lay insulation between the battens and nail the oak finish floor down the advantages are:
1/ Ease to lay battens. 2x2 softwood battens are easy to handle transport, drill and cut. Fixing to the existing boards can be done with a handsaw, and a decent cordless drill.
2/ Easy to level. If the floor is slightly uneven, throw a straight edge (not necesarrily a spirit level) across the battens, and pack the battens using thin offcuts, or cut some wedges.
3/ Easier to get at services running underneath existing floor boards.
4/ Floor will feel more solid, as it is fixed to a solid ground.

Disadvantages are:
1/ Level of sound proofing less effective: general noise levels (from music, talking etc) will be reduced, although traffic noise through walking around will only be reduced slightly.

If you insulate, and then lay ply boards on top, followed by the finish floor, then advantages will be:
1/ Far more effective level of sound deadning.
2/ Floor will feel more "damped" as you walk on it.
3/ Insulation can be laid easier, cutting only around perimeter of room rather than ripping to 16" strips to fit between battens.

Disadvantages are:
1/ Difficult to remove any irregularities if the existing floor is not flat. The insulation would have to be laid, and the ply would have to float on top of the insulation, therefore the floor is not fixed to a solid ground. Result: more bounces and squeaks.
2/ Difficult to nail the oak to the ply. Oak is a hardwood, and ply is pretty difficult to nail into, especially when the ply is floating on insulation. You can pilot drill first, but adds lots of time. Result: loads of bent nails, spoiled edges, bust fingers and the loss of will to live.
3/ Ply T&G boards are far harder to handle and transport than battens, and involve fitting to the perimeter of the room, ten times the time.
4/ Cost. Ply boards will be far dearer than softwood battens, plus glue etc.
5/ Time. Will undoutebly take far longer to lay.
6/ Because the oak is planted straight onto the ply with no air gap, air can only properly get to one face of the board. Hence moisture can only can only escape/absorb on one face, the face lying against the ply will sweat and "cupping" will occur.
7/ This method results in a thicker floor, hence ceiling heights, and more importantly door heights will be lower.

If you decide on this method, remember to lay the ply boards in the opposite direction to the oak boards.

I would not normally leave an expansion gap between each 5" oak board, unless the boards are VERY dry, which I doubt. Hardwoods should be kiln or air dried to a moisture content of around 8/10%, a little more than what you would find in a centrally heated environment. Therefore 99 times out of 100 shrinkage occurs- for fine joinery work, shrinkage is infinately more preferable to expansion. However DO leave a small expansion gap (around 7-8mm) at the perimeter, only required along the length of the board, not the ends. Timber expands/contracts in width only, never length. Cover with skirting board.

Nail the boards at around 12-16" centres (300-400mm), this should be fine. You will need a decent hammer and a good nail punch.

Let me know if you need any advice on finishings.

The best of British!

[Edited by Olly - 5/24/2002 1:24:10 PM]

fast bloke

Hire a nail gun - keeps the will to live - Secret nailing into the angle of a tongue with a nail punch will be sould destroying. I got one with an adjustable nail angle, so you set it to 45 degrees, put the front onto the tongue and press the button - next - also saves hammer marks on the floor (or thumb) where you invarible miss

IanWatson

Olly/Fastbloke - fancy a weekend laying floors in Amsterdam?
All food/drink and entertainment included!

Will deffo sort out a nailgun - banging thousands of nails in with a hammer isn't likely to improve my guitar playing!

The plastering needs to be done before the floor, so I'll be starting in 2/3 weeks - any more probs, I know where to ask.

Thanks for all the help - this really is a great community

fast bloke

I would love to do it, but my better half would get really upset if I left the house with no roof to go and play in Hamster Jam for a few days

IanWatson

Ah well - hadn't actually mentioned the suggestion to my better half either..

Olly

Nail guns are for girls A couple of broken fingers never hurt anyone .

Seriously though, wise move. Go and rent a compressor and nail gun, you won't regret it. Quicker, easier and potentially less damaging.

We have a similar device, however instead of a firing pin thrown by compressed air, ours is a manual nailer with a big striker, hit with a large mallet. Benefit being the blow from the mallet knocks the joint up tight as well as strikes the nail. Perfect for stress relief and right hand/arm exercise as well. Not that I need the latter..

CrisPDuk

Olly, you muppet, nail guns are for lazy ba***rds, that is why you own a double barrelled one

P.S. I am impressed, 5 posts on a joinery thread and you haven't mentioned liquid nail once

Olly

I always wondered why I get a birthday card from Dow Corning and Liquid Nail.

Anyway, double barreled nail guns are only useful for firing at apprentices.

CrisPDuk

Why dont' you use the bonehead's hand to hold the nails whilst you hammer them in

IanWatson

spoke to the boss on Friday - sorted a 4 day for the next few months 'til the flat is sorted

Good job I did - had the Thermacell acoustic flooring 'delivered' today - 2.5 pallets weighing 1.2 tonnes EACH just dumped on the pavement.

Had to shift all three tonnes (150 sheets - one at a time) up to the first floor - the bloody wirewool layer was like raw glass fibre..

Wouldn't have minded that much had it not been thunderstorms all day

Do they do a Gattling-style nail gun for laying floors?

fast bloke

Ian - Welcome to the wonderful world of home improvement. I got 4 pallets of brick and 2 of blocks delivered last week. 1200KG each. The delivery driver thought it was a good idea to leave them across the front of the drive. The brickies didn't want to cary them onto the roof as they might get their likkle soft hands dirty, so your truely spent the weekend shifting 7.2 tonnes of brick and block up 16 foot of scaffolding. Now I've got forearms like Popeye

CrisPDuk

Well thats how he 'says' his forearms got like that

Mog

Eh fast bloke let me know where I can buy 18mm ply in 8x4 sheets for only 3 squid.....?

IanWatson

I was going to ask the same - things are generally a lot cheaper here, and I can't find large 18mm t&g plysheets at that price!!

How's your back today FastBloke?