Big Neil

Stud Walls - and Floor Structure

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I don't quite understand something surrounding stud walls - So.  ON my newbuild estate, they build the houses in a traditional manner, brick and block, cavity wall. When they get to the first floor level, the either (i assume depending on the house design) either crane in ready assembled floor panels, or more often, place I-joists, then glue/nail weatherproofed chipboard on top. Following this, the rest of the walls go up, the roof goes on and only when the tiles are on, are the interior stud walls erected (on the first floor anyway.

 

So this tells me that they  construct the walls which are nailed/screwed straight on top of the floor itself. So firstly, why is this done instead of putting said walls (nominally standard 2X4 timber studs) on top of the joists directly, then adding in 'noggins' (if that's still what they're called when in a floor not a wall), around the perimeter of a room, to support the edge of the floor boarding? IS either method more wrong or right than the other?

 

It strikes me that when constructing the separating walls on top of the floor boarding, that gives potential issues later on if you happen to need to make modifications, or get to an issue. Is this just misinformed?

 

Next point. Although it seems most volume built new houses, use chipboard flooring panels, usually glued to the top of the joists. I’ve always found when helping to remove these for whatever the reasons that the gluing not only tends to contribute to the board not coming up cleanly, but seems to flex more than other materials. My father for example who has replaced the entire upstairs of his 4 bed, used I think 18mm structural ply. It’s pretty solid, no noise, no apparent flex or owt.

 

What is the preferred and generally better option, and why?

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It is safer to have the floor in as a working platform.  If you later need extensive access it will be from the ceiling below.

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It would be far easier to chipboard a whole floor than cut around numerous studs etc.

 

There is no reason why a person in the future can't cut through the chipboard and support the edges if say they needed to move a pipe etc

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Posted (edited)
4 hours ago, Mr Punter said:

It is safer to have the floor in as a working platform.  If you later need extensive access it will be from the ceiling below.

I get the safety aspect, but one could either compensate for this to a degree - so a crash deck for example, a fall arrest system attached to the rafters or maybe just a 7 foot pile of old mattresses with a peas underneath. In either case, why restrict ones access if there is an alternative

 

3 hours ago, bassanclan said:

It would be far easier to chipboard a whole floor than cut around numerous studs etc.

Juzst like it would be easier to buy a bottle of pop instead of a sodastream, but people can choose whichever system they want

 

3 hours ago, bassanclan said:

There is no reason why a person in the future can't cut through the chipboard and support the edges if say they needed to move a pipe etc

Why put a system in place which could later create issues where they could otherwise be avoided, by changing ones approach? 

 

if of course there's a fundamental reason for putting the wall on-top of the flooring AFTER the floor has been put down, then fair enough.

Edited by Big Neil

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2 hours ago, Big Neil said:

I get the safety aspect, but one could either compensate for this to a degree - so a crash deck for example, a fall arrest system attached to the rafters or maybe just a 7 foot pile of old mattresses with a peas underneath. In either case, why restrict ones access if there is an alternative

 

Juzst like it would be easier to buy a bottle of pop instead of a sodastream, but people can choose whichever system they want

 

Why put a system in place which could later create issues where they could otherwise be avoided, by changing ones approach? 

 

if of course there's a fundamental reason for putting the wall on-top of the flooring AFTER the floor has been put down, then fair enough.

point 1 - cost

point 2 - cost

point 3 - cost

point 4 - cost

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2 hours ago, Big Neil said:

Why put a system in place which could later create issues where they could otherwise be avoided, by changing ones approach? 

 

It won't be their issue, it will be someone else's.  

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2 hours ago, Big Neil said:

if of course there's a fundamental reason for putting the wall on-top of the flooring AFTER the floor has been put down, then fair enough

 

Structural integrity.

 

The floor is glued to the beams which makes it a structural member. If you left holes then you would have stress points and a non structural member and may flex and creak. 

 

For walls running perpendicular to the joists then noggins are not required - run parallel to the joists and not directly over then you need noggins. 

 

7 hours ago, Big Neil said:

My father for example who has replaced the entire upstairs of his 4 bed, used I think 18mm structural ply.

 

So I hope his joists are at 400 centres, or its 22mm, as 18mm is not thick enough at 600 centres. 

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38 minutes ago, PeterW said:

So I hope his joists are at 400 centres, or its 22mm, as 18mm is not thick enough at 600 centres. 

 

18mm ply is acceptable at 600 joist ctrs.

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49 minutes ago, Mr Punter said:

 

18mm ply is acceptable at 600 joist ctrs.

 

Sorry, read it as chipboard not ply ..! 

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2 hours ago, Simplysimon said:

point 1 - cost

point 2 - cost

point 3 - cost

point 4 - cost

of course i'm not suggesting money should be spent frivolously, but if cost was the only consideration, surely we'd all be living in communes of shipping containers lined with recycled newspaper for warmth and cuddling our childhood teddy bears for comfort

 

2 hours ago, Hecateh said:

It won't be their issue, it will be someone else's. 

seems like a poor reason to maybe do something incorrectly. would we not all be livid if a professional did something poorly because of that same attitude? I read a post on here about someone whose floor tiling was screwed up by a mate of their PM. Seems that was his attitude and a lot of the tiling chaps on here were appalled

 

2 hours ago, PeterW said:

Structural integrity.

 

The floor is glued to the beams which makes it a structural member

right you are, so external walls up, roof on, joists in and then board out the first floor (albeit with maybe some other bits in between such as laying UFH etc?

 

And would you be screwing or nailing them aswell as gluing. Alternatively would you just use that tape like stuff on top of the joists to prevent squeaking, then just nail or screw them down?

 

What to the last and maybe most crucial point about flooring type? Chip or Ply, whatever the relevant thickness?

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22mm chipboard with d4 glue and plenty of screws. 

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2 minutes ago, Big Neil said:

seems like a poor reason to maybe do something incorrectly. would we not all be livid if a professional did something poorly because of that same attitude? I read a post on here about someone whose floor tiling was screwed up by a mate of their PM. Seems that was his attitude and a lot of the tiling chaps on here were appalled

 

 

definitely a poor reason, I totally agree.  BUT - 

I started with a main contractor (or that was how he styled himself - and he believed he could do this BUT (it was beyond his experience).  SO after water tight, I (with zilch knowledge or experience)  took over project management. 

The joiners that did the stud walls blamed the builders for being out of square.  BUT built stud walls in the wrong place (corrected at mostly my expense) but apart from that, built walls that were not true (obvious bows once plasterboard was in place) and didn't allow for dot and dab when building above blockwork. 

 

The first plumber I engaged had little experience beyond 'pretty work' but thought she deserved high skill wages and charged ultra high prices for sub standard work.

 

The plasterer, who was great in general, clogged up some of the first fix electrics - not insurmountably, but the spark says he oftens finds first fix totally plastered over.  etc, etc.  

 

In summary ----- trades blame the one before and leave crap for the one after.  Not 100% true, - age/life experience -  seems to me to be a factor, as more experience often leads to more consideration. 

I have now got (I believe) good plumbers, electrician, general (high skilled) handyman who are aware of the effect their work has on others.  BUT

 

You either pay more and get a project manager who (hopefully) cares and co-ordinates it all or do it yourself and find (after the event) that some only care about their own trade and not the ones coming after.

 

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I really believe that if most people had a little bit more understanding about how things SHOULD be done, there would be less shoddy tradespeople around because they'd never be hired as people would know more about what was and wasn't acceptable. 

 

One of the things that had me asking about this was trying to understand  the timing and process of installing underfloor heating with spreader plates upstairs. Seemed like it would involve less error putting walls up THEN putting down spreader plates etc etc.

Logically speaking that still seems correct, particularly given that people are saying 'well if work is needed at a late point just cut the board and pull it up'. Seems a bit like saying you want decent structural integrity while you're erecting a building but if something goes wrong at a later point, well (expletive deleted) the structure just cut bits out and patch it up. I'm sure Peter is probably right, but for the novice I can understand (given that I am one) how general good practice, can seem counter intuitive when opposed to another seemingly reasonable option. I had previously though the existence of load bearing internal walls, an out skin whatever the type, and installed floor joists of the relevant size, was in itself enough structure. I now stand corrected.

 

Tomorrow's question - Is it ok to have my toilet, in the middle of my kitchen???????

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51 minutes ago, Declan52 said:

22mm chipboard with d4 glue and plenty of screws. 

Thanks - I'll look up D4 glue as I've currently no idea what it is - I thought D4 was Eminem's crew

 

So is there a particular reason why you say chip board and screws as opposed to say Ply and Nails for example. Is it personal preference or is there something i'm missing?

 

ooooo - is D4 glue that stuff that foams up??? Will this method actively prevent squeaks?

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also- is tongue and groove preferable or not and in either case, why??

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Chipboard will come in 8*2 so easier to move about. 22mm thick will still be heavy. 

It will be p5 rated so will be moisture resistant. 

Always found it locked together better than t&g ply. 

D4 glue foams up as you say to fill every gap. It's really really strong glue. Once down and cured you would struggle to pull a sheet up.

For this application screws is you choice. You can get screws that won't need a pilot hole so won't split the board and will self countersink so will sit flat.

If your joists are at 400mm centers with a 22mm chipboard floor glued and screwed you could park your car on it. It will be rock solid.

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Why would you build the studs then floor around. You don't seriously expect any builder let alone a volume builder to build with future alterations in mind as strongly as that. Some foresight is acceptable i.e. I accept trimmed out floor openings for potential lift access then joisted and decked is ok. Some LA's ask for this now. But flooring around stud walls on the basis that some punter who's the third owner of the house 20 years later might need to move a room which still means ripping up flooring anyway and altering plumbing and elec?! Crazy. Suspended ceiling tiles on gf next!

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On 05/10/2018 at 22:45, Big Neil said:

I really believe that if most people had a little bit more understanding about how things SHOULD be done, there would be less shoddy tradespeople around because they'd never be hired as people would know more about what was and wasn't acceptable. 

generally the populace don't care. goods are disposable, if it looks nice that's all that matters. house builders are there to make a profit and return a dividend to their shareholders not to make life easy for third owner as stated previously. 

On 05/10/2018 at 22:45, Big Neil said:

 

One of the things that had me asking about this was trying to understand  the timing and process of installing underfloor heating with spreader plates upstairs. Seemed like it would involve less error putting walls up THEN putting down spreader plates etc etc.

Logically speaking that still seems correct, particularly given that people are saying 'well if work is needed at a late point just cut the board and pull it up'. Seems a bit like saying you want decent structural integrity while you're erecting a building but if something goes wrong at a later point, well (expletive deleted) the structure just cut bits out and patch it up. I'm sure Peter is probably right, but for the novice I can understand (given that I am one) how general good practice, can seem counter intuitive when opposed to another seemingly reasonable option. I had previously though the existence of load bearing internal walls, an out skin whatever the type, and installed floor joists of the relevant size, was in itself enough structure. I now stand corrected.

good practice is all well and good but cuts profit

On 05/10/2018 at 22:45, Big Neil said:

 

Tomorrow's question - Is it ok to have my toilet, in the middle of my kitchen???????

absolutely, but wait until BC sign the building off first!

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On 06/10/2018 at 11:14, Oz07 said:

hy would you build the studs then floor around. You don't seriously expect any builder let alone a volume builder to build with future alterations in mind as strongly as that. Some foresight is acceptable i.e. I accept trimmed out floor openings for potential lift access then joisted and decked is ok. Some LA's ask for this now. But flooring around stud walls on the basis that some punter who's the third owner of the house 20 years later might need to move a room which still means ripping up flooring anyway and altering plumbing and elec?! Crazy. Suspended ceiling tiles on gf next!

 

To be fair I was asking because I didn't know, and never said it was something volume builders SHOULD do, or that i wanted to consider the convenience of a future owner. It jyst seemed like it was a reasonable method.

 

@Declan52 - so 8 X 2, T+G, P5 rated chipboard. Why tongue and groove and not straight edged?

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With t&g you don't have to have the join of each board on a joist. It makes the floor when it's fully glued up one solid piece so very strong. Also if you use d4 glue it will expand and fill each groove so the floor won't let any draughts through. 

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Just seen this @Declan52 - thanks. So essentially, short edge of the board as will always be flat, to end on a joist, but as the long edge will be perpendicular, needs to be tongue and groove. Sorry to seem dense but I just want to be sure. Seems there are so many products out there and everyone seems to have broadly conflicting opinions. I'm still a bit conflicted of course, having seen structural ply used before.

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5 minutes ago, Big Neil said:

Just seen this @Declan52 - thanks. So essentially, short edge of the board as will always be flat, to end on a joist, but as the long edge will be perpendicular, needs to be tongue and groove. Sorry to seem dense but I just want to be sure. Seems there are so many products out there and everyone seems to have broadly conflicting opinions. I'm still a bit conflicted of course, having seen structural ply used before.

 

Nope - all are T&G all round so you can float short edges as you brick bond the boards so there is no 4 point joints. 

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All 4 sides of t&g ply have tounges/grooves.

You start with a flat edge against a wall then work away staggering joints

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Yeah just work out a rough run of how they will sit. You don't want to end up with a tiny cut each time. The bit you cut from one run is your first piece in the next run. Means you have very little waste with the only length cut when you get to the opposite wall.

D4 glue is quick to set so don't be going ahead more than the board you are laying.

Just put a screw in each corner and one  in the middle to hold it in place. Mark the middle of the joist on the board so you can strike a line across and go mental with the cordless when they are all down.

Or if you can get another pair of hands they can be banging in the screws as you lay the boards.

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