Is this tradesman trying to increase the size of the job? Flooring related.

[Ekim]

We are currently in the process of renovating our conservatory after fixing a leak at the start of the year. We have had everything replastered and are now in the process of sorting out the floor which has sunken in one corner, due to I assume the leak warping the chipboard subfloor.

We were considering getting Karndean laid in the conservatory and have had three people round to quote for the work.

Two of the people who came over (one who was unable to see the subfloor as I hadn't lifted the old floor at the time), quoted for the work without issue.

The third person who came over has listed out a number of issues and I am unsure how serious the issues are or if he is just trying to increase the size of the job.

The issues he has indicated are:

1) At the moment the joists are 60cm apart (based on the screws visible on the chipboard). The third person thought that actually the joists should be 40cm apart. At 60cm apart we are running the risk of the floor being uneven and 'wavy'.

2) Chipboard is an unsuitable material for the subfloor and should be completely replaced with plywood.

3) Karndean isn't suitable for a conservatory and that as the heat gets to it it'll contract/expand and cause issues with gaps appearing in the floor.

It feels like the third guy might just be trying to make it a bigger job for himself (although having spoken to him on the phone he says he wouldn't normally do the joist stuff himself and would get a builder to do it).

 

[touch]

The karndean installation guidelines are here.
They say that chipboard is an unsuitable material for the subfloor but you can overlay it with 6mm plywood rather than replacing the entire thing.
Also says that in fully-glazed conservatories the flooring should be epoxied down.

If you're spending a lot of money on the flooring, it's worth paying a bit extra and having the subfloor done properly IMO.

 

[Ekim]

Thanks for that. The conservatory isn't huge (~2.7m x 2.5m) and the quotes for the flooring and installation have come in around £600-£700 so far (the third tradesman hasn't given a quote yet for all of the work that he is recommending).

One of the flooring fitters have included plywood in their quote so I assume they were planning on covering the subfloor with it. The installation guide is interesting actually given the conservatory is absolutely freezing cold at the moment I wonder if we could actually bring it up to and keep it at the recommended temperature.

Do you think the whole joist thing is something we should get fixed, or is it just over-egging what needs to be done?

 

[Buffman]

I've had some laid with details in my "bungalow build log" thread. They just put 6mm over the previous subfloor.

Maybe the third bloke doesn't want the job?

 

[Ekim]

I've had some laid with details in my "bungalow build log" thread. They just put 6mm over the previous subfloor.

Maybe the third bloke doesn't want the job?

Thanks will take a look at your thread.

The third guy has spoken to me a few times etc. and seems keen on the work - I'd figure if he wasn't interested he'd have just given me a huge cost for the work. Last time I spoke to him he wants me to lift the subfloor to look at the joists so he can quote more accurately!

 

[Cosmic182]

600-2ft for floor joists is far to big of a span. Unless you’re planning on putting some extremely thick ply down the third chap is talking perfect sense. 400 centers is the go to.
If you’re spending that much on karndean, donit properly and don’t skimp or it will come back to haunt you.

 

[Ekim]

600-2ft for floor joists is far to big of a span. Unless you’re planning on putting some extremely thick ply down the third chap is talking perfect sense. 400 centers is the go to.
If you’re spending that much on karndean, donit properly and don’t skimp or it will come back to haunt you.

In term of sorting out the joist issue then, would it be a case of installing new joists between the old ones so they will be 300mm centres, rather than moving the old joists etc.?

 

[toprock]

Thanks for that. The conservatory isn't huge (~2.7m x 2.5m) and the quotes for the flooring and installation have come in around £600-£700 so far (the third tradesman hasn't given a quote yet for all of the work that he is recommending).

One of the flooring fitters have included plywood in their quote so I assume they were planning on covering the subfloor with it. The installation guide is interesting actually given the conservatory is absolutely freezing cold at the moment I wonder if we could actually bring it up to and keep it at the recommended temperature.

Do you think the whole joist thing is something we should get fixed, or is it just over-egging what needs to be done?

Do you know what sort of price per m2 the floor itself is? Sounds a lot for a room of that size, or the labour sounds high one of the two!

 

[Ekim]

Do you know what sort of price per m2 the floor itself is? Sounds a lot for a room of that size, or the labour sounds high one of the two!

£26.99 from one fitter, £23 from the other. I think based on the pack sizes they have to order around 10m2. One has also quoted for laying ply on the subfloor the other has just quoted for latrex screed.

 

[FurryLemon]

I'd certainly consider #3 as he pointed out a number of issues instead of just being a 'yes man' to get the work.

 

[Nathan]

Me too. He seems thorough and flooring is so important to get right. I recently spent 6k on my downstairs flooring. Not even that big at 80SQM.

 

[brendy]

As above, 30cm gaps between joists, marine ply boarding (two layers running 90 degrees to eachother if you can afford it to prevent as much floor movement as possible) and it should be a good job.

 

[Ekim]

Pulled up some more of the old floor last night to see if there is a way I can pull up the chipboard to see what is going on underneath. Can't see a way just yet but will probably pull up the rest of the floor on the weekend.

I've also been in touch with a couple of builders about doing the joist work so will see what they come back with in terms of quotes. The floorer who mentioned the issue when I spoke to him yesterday said that this wasn't the type of work he'd typically do - although he seemed confident enough he could do it.

 

[MassiveJim]

joist spacing is based on a few factors
1 - joist span (the length the joist runs unsupported)
2 - the joist thickness (thicker joists can bear more weight so can be spaced further apart)
3 - the sub floor thickness (the further the joists are apart the thicker the sub floor will need to be) although you can put additional noggins in to compensate (to a degree)

There are minimum requirements for joist thickness and spacing in Uk building code, always go above what these say.

I have almost completed my loft now and the guidelines suggested that I could use 7x2 joists at the spacing I wanted to, I used 8x2 instead and the floor still has a degree of movement (flex) in it despite me using the thicker joists, albeit very minimal movement.
I'me sure 8x3 or 9x2 would have completely eliminated any movement at all

 

[MassiveJim]

Pulled up some more of the old floor last night to see if there is a way I can pull up the chipboard to see what is going on underneath. Can't see a way just yet but will probably pull up the rest of the floor on the weekend.

I've also been in touch with a couple of builders about doing the joist work so will see what they come back with in terms of quotes. The floorer who mentioned the issue when I spoke to him yesterday said that this wasn't the type of work he'd typically do - although he seemed confident enough he could do it.

Fitting joists isn't the most difficult job in the world to be fair, I'm certainly no builder and I managed (with my brothers help) to fit 7 or 8 joists myself on joist hangers as well as bolting the wood to the wall that they hang from and chemifixing the bolts in the wall.

 

[Bickaxe]

Karndean should do a heat resistant adhesive. Make sure that is used.
Its been a few years now since i worked in the industry but i remember 1 flooring issue when they wouldn't pay out as the wrong adhesive was used which was the cause (in a conservatory).
Quotes seem reasonable for the size with prep included. I would go with a layer of ply as a smooth subfloor is required and with screed it can not be guaranteed (even with floor levelling).

 

[Ekim]

Fitting joists isn't the most difficult job in the world to be fair, I'm certainly no builder and I managed (with my brothers help) to fit 7 or 8 joists myself on joist hangers as well as bolting the wood to the wall that they hang from and chemifixing the bolts in the wall.

I just don't have the time, and don't have anyone locally I could get in to help me to do it. I'd rather pay someone to come and do it properly and try my hand at it in the future when I have a little more time.

Karndean should do a heat resistant adhesive. Make sure that is used.
Its been a few years now since i worked in the industry but i remember 1 flooring issue when they wouldn't pay out as the wrong adhesive was used which was the cause (in a conservatory).
Quotes seem reasonable for the size with prep included. I would go with a layer of ply as a smooth subfloor is required and with screed it can not be guaranteed (even with floor levelling).

One of the quotes I have at the moment specifically mentions Karndean adhesive - this is a quote from a floor shop recommended by Karndean so assume they are doing everything as per Karndean's instruction

 

[MassiveJim]

I just don't have the time, and don't have anyone locally I could get in to help me to do it. I'd rather pay someone to come and do it properly and try my hand at it in the future when I have a little more time.

sorry I wasn't suggesting you do it yourself, i was more trying to re-assure you that if the vinyl fitter is confident doing it, not to worry too much as its not a complex job.

 

[GinG]

I'd certainly consider #3 as he pointed out a number of issues instead of just being a 'yes man' to get the work.

I was just about to say the first thing. The other 2 seem to be more than happy to just do the job without thinking...if I read correctly one even quoted without seeing the subfloor.

#3 seems to be the one who has pointed out exactly as per the Karndean flooring guidelines, and in my opinion the one most bothered about doing the job right.

 

[booyaka]

I had to get 6mm ply down before karndean flooring was glued down in my kitchen/diner etc - cost more than expected but a great job and done properly.