Laminate flooring and use of Dpm or vapour barrier

[pritsuk2002]

Hi I have fibreboard underlay in the instructions for the underlay it states if using this product on ground floor you should also use vapour barrier or damp proof membrane beneath the underlay. The ground floor is wooden floor boards and there are 2 rooms I need to do. There is a small section along the chimney where the gas fires are. One has a concrete section and the other gas fires section I believe is a latex base.

On the laminate instructions it states when laying laminate over a mineral surface eg concrete, cement scread etc extra care should be taken. Fit a dpm between mineral floor and underlay then lay laminate

1. I wanted to know if I do need to use the dpm or vapour barrier or can I go ahead without it?
2. If I do need to use it do I need to install it on the entire rooms floor or just in the concrete and latex sections?
3. What are the pros and cons of not using it and using it?

Here is a pic of the mineral area

Untitled

• pritsuk2002
• 15 Feb 2015
• 1

Any help on this topic is greatly appreciated thanks

 

[dazlight]

I would use some on the fireplace. Not over the floorboards.

 

[pritsuk2002]

Thank you does it need to be put up behind the skirt? I dint want to remove the skirtingboard as its painted. Also would the dpm need overlap onto the wooden floor board or end on the concrete section? And finally would dpm or vapour barrier be better.

Also does this only apply for ground floor as 2 bedrooms upstairs have similar areas and I will be laminating them aswell?

Thanks again for your help and any more info or views and opinions are still welcome

 

[dazlight]

Hi , no it doesn't need to go upstairs. It's for raising damp form the ground floor.
Put DPM sheet on concrete overlapping onto floorboards 12". It won't need to go under skirting. Chances are there will be no moisture coming up anyway but best to be safe

 

[pritsuk2002]

http://www.wickes.co.uk/Wickes-1000-Gauge-Black-Damp-Proof-Membrame-4x3m/p/152858

Thanks so just to confirm the upstairs areas which have the concrete areas just like downstairs will not need damp proof membrane i only need it on the concrete areas downstairs is that correct?

I have found one in the link will that be ok? It states ok for concrete but not for wood will I have problems with 12" overlap onto wood?

On the site they advise using bitumen backed building paper on wood areas will I be ok not using this or should I use it especially it being ground floor?

http://www.wickes.co.uk/howtoguideflooring

Another thing I noticed was one floor board is thinner so I have a dip can I use marine ply and nail or glue it over the dipped floor board so it more level or any better solutions. I have included a pic of the dipped floor board its marked with a green peice of tape. I think someone has used a different thickness board tbh.



Thanks again for your help and sorry for the questions I just want to make sure I do it right and not have any problems after

Untitled

• pritsuk2002
• 15 Feb 2015
• 1

 

[pritsuk2002]

http://www.wickes.co.uk/Wickes-1000-Gauge-Black-Damp-Proof-Membrame-4x3m/p/152858

1. Will this be suitable for the dpm application for the fireplace concrete floor?

2. It has more than what I need. Can I use it for the concrete sections upstairs or will it cause damage as you have advised not needed but ive got spare. So would it do any harm to use it upstairs for the concrete sections?

3. So on the floor the dpm will overhang by 12"all the way around?

4. What about the side that meets the wall. Does it get cut at bottom of skirt? Or run up behind or in front of the skirt? Does it get trimmed back?

5. What is used the seal and fix it to the floor and wall side? Or is it just loosely laid?

Thanks again for all you help

 

[dazlight]

It's hard to say to be honest. It depends if there is high moisture in the cincrete.
You can overlay about 6". I have used a builders bag to do this is will still work. Just helps to stop moisture getting into the underlay.

You can tape to skirting at bottom with vapour tape, duck tape will do.
The upstairs slap will be dry so no need to worry.

 

[HawkEye244]

A moisture/vapour barrier is not really needed at all because even in the ground floor you have (provided the joists are in good condition) there is no moisture to keep out. Putting it over that small fireplace area really achieves nothing. In fact you may end up causing problems by putting that down. As for the occasional dips/ troughs in the floor, no need to worry, the laminate all locks together as one body so it won't make the slightest difference. I would not bother trying to level the floor before applying the underlay for this reason, as long as all lose screws/nails are down firmly you will be fine

The instructions are mainly trying to impose the importance of laying a DPM where the laminate is fitted to concrete, in your case it's really not important because it's NOT solid, it's suspended timber and there will be airing bricks underneath removing moisture =)

 

[dazlight]

I have to disagree with that.
Any dips more then 5mm over over 1metre it can cause the laminate to bounce. Which in turn can weaken joints an cause them to break. Repaired quite of few floor where this is happened.
So they should be filled with more underlay or s Screeding compound.

The concrete fireplace it would depend if any moisture is it it. Most of them all direct to earth.

 

[HawkEye244]

I have to disagree with that.
Any dips more then 5mm over over 1metre it can cause the laminate to bounce. Which in turn can weaken joints an cause them to break. Repaired quite of few floor where this is happened.
So they should be filled with more underlay or s Screeding compound.

The concrete fireplace it would depend if any moisture is it it. Most of them all direct to earth.

In honesty I've only fitted laminate to concrete bar one small room so I can see what you mean. By screeding compound you mean leveling compound applied on top of a layer of ply?

I'd like to see how you successfully fill out with just underlay to get an even and flat surface, that's not within my skill level tried it, was horrendous

 

[pritsuk2002]

Ok I have almost finished installing I did use a dpm over the fireplace and used some tape to secure ot to the floor. I did have a dipped floor board which I covered with exteria ply and extra fibre board. So I hope its ok, tbh I wanted to lay the floor so if needed to be pulled up it cn be done without much problems from either side of the room so I didnt undercut frame.