Advice needed- self leveling compound over existing compound

[Shoganator]

Hi all,

Re-doing our kitchen floor and its the first time I am tackling this type. The old flooring was vinyl sheet, and I am going to lay vinyl plank down in its place.

After removing the vinyl sheet, I found that self leveling compound was previously used. Another issue is that kitchen units have been moved around and the layout of the kitchen changed, so there are some areas that are lower now where the old kitchen units used to be placed (the compound was not poured in these places, so they are 1 or 2mm lower).

I have two questions:

1. Can I pour new self leveling compound over the existing (few years old) self leveling compound?

2. Should I rather just fill the gaps where the old units used to be with new compound to get them as close to the level of the existing stuff?

Couple of things I noticed: the old compound is crumbling a bit on the edges, and there is sticky tape/adhesive where the old vinyl flooring was held down - how should I handle these?

Here are some pics to illustrate the slightly lower part where old unit was placed, and the crumbling edges...

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• Shoganator
• 22 Sep 2013
• 1

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• Shoganator
• 22 Sep 2013
• 1

 

[dazlight]

Good pictures them.
As long as the screed that's down is well bonded then you be better to

Scrape up any loose screed.
Prime the areas that aren't screeded
Screed the areas which have screed missing.
Prime the whole floor
Screed the floor.
For a LVT ( vinyl planks ) the sub floor has to be perfect.

Does the sub floor have a exsisting dpm?

 

[Shoganator]

Good pictures them.
As long as the screed that's down is well bonded then you be better to

Scrape up any loose screed.
Prime the areas that aren't screeded
Screed the areas which have screed missing.
Prime the whole floor
Screed the floor.
For a LVT ( vinyl planks ) the sub floor has to be perfect.

Does the sub floor have a exsisting dpm?

Hi dazlight,

Thanks for the info.

I believe it has an existing damp proof membrane, as on the outside of the building I can see the line indicating a damp proof course.

So you reckon I should prime the areas missing screed first? What primer is generally a good one to go for? I also have a Gerfloor primer in a bottle (came with the vinyl plank flooring) which I assume I need to put down on top of the final layer of screed once that is dry?

With regard to the final layer of screed to smooth everything off, then adding the vinyl plank on top of that, have you got any advice for me regarding the plynth under the edges of the kitchen units? One piece was quite tight coming out - I'm worried that adding another layer of screed down will make it impossible to fit back in. I guess I might have to just chop or plane a thin layer off the bottom to get it to fit if it doesn't after the flooring is down...

 

[dazlight]

The damp course the outside mate is for the walls not the floor.
If you take the skirting off you should see a visqueen sheet around the edges. That's the floor dpm.
Think the gerfloor bottle you have might be polish or floor dressing for the planks and not a primer. Just with you saying it came with the planks.

You are best taking all the plinths off then after you have fitted the floor put them back on. You might have to plane a few of them.

As you will be screeding over old adhesive then a good screed will be needed like
Ardex NA or F.ball 1200 pro. Both are a low compression strenght and good for bonding to old adhesive.

 

[Shoganator]

The damp course the outside mate is for the walls not the floor.
If you take the skirting off you should see a visqueen sheet around the edges. That's the floor dpm.
Think the gerfloor bottle you have might be polish or floor dressing for the planks and not a primer. Just with you saying it came with the planks.

You are best taking all the plinths off then after you have fitted the floor put them back on. You might have to plane a few of them.

As you will be screeding over old adhesive then a good screed will be needed like
Ardex NA or F.ball 1200 pro. Both are a low compression strenght and good for bonding to old adhesive.

Ok, found the dpm - thanks for describing it! Yes, definitely is a sheet around the edges sticking out behind the skirting.

The gerflor bottle was recommended to get with the flooring, so I added it with my order - sorry worded that one wrong. It's definitely a primer to help the vinyl planks with adhesion. It's called "Gerflor Primer Performance".

Thanks for the recommendation on the screed - I'll take a look at both options you mentioned and get one of those. Seems like a lot of effort, but with everything, I guess it'll pay to put in the time and effort.

Cheers!

 

[dazlight]

Nice one hope it goes well. It is a lot of effort mate to be honest.
Like I said the key to these floor is getting the prep correct. Even screeding is a art. Taken me a lot of years to get it perfect.

Have you screeded before? If you can borrow a spike roller. Really helps getting a good finish on the screed.

 

[Shoganator]

Nice one hope it goes well. It is a lot of effort mate to be honest.
Like I said the key to these floor is getting the prep correct. Even screeding is a art. Taken me a lot of years to get it perfect.

Have you screeded before? If you can borrow a spike roller. Really helps getting a good finish on the screed.

I haven't screeded before, no. I read up about the spiked roller, so will have a look into finding one. Cheers again for the help and advice, very much appreciated! Its a small kitchen so hopefully be a good starter project to get stuck into!

 

[dazlight]

Good luck mate, get some progress pictures up.

 

[Shoganator]

Progress...

Just put down the screed after having primed beneath. I went up to the edges of the plinth's after first masking the bottom of the plinth along all edges, and filling the gap between plinth and floor with silicone - so that none of the plinth soaked in any moisture from the new screed.

After a couple of hours it is looking dry, but I'll wait the full 24 hours before using the "Gerflor" primer that I got with the Gerflor vinyl planking on the surface of the new screed.

The levelling compound/screed I used is F-ball Stopgap 1200 Pro. Used a full 20KG bag along with the 5L liquid mix, bought a mixing paddle for my corded B&D drill from Screwfix to mix it all up for a 4 or 5 minutes, then poured it all down started at the back of the room, then moving back as I went. I had a plastering trowel to help spread it a bit, but I didn't need to use it a lot. No spiked roller unfortunately, but its looking smooth enough!

New screed down

• Shoganator
• 20 Oct 2013
• 1

New screed down - using f-ball stopgap 1200 pro.

My idea is that the plinth helped me form a border so that I didn't run out of screed, and after this has dried I'll remove the plinth, and lay the vinyl plank flooring down so that it bleeds out under the plinth area by a couple of inches. Obviously it'll drop down a few mm's after it goes over the edge of the new screed, but that is fine, as the plinth will be covering that, but by doing this, it should look neat, and not be cut off right where the plinth starts, but rather flowing underneath the plinth. Does this sound like an OK plan ?

 

[phatboy]

Just a minor point... you mentioned planing the bottom off the plinth. Better to plane off the top edge as the bottom should be factory finished, and so water resistant. If you plane the bottom off any water that hits the plinth at the bottom will get into it and cause it to bubble....

 

[Shoganator]

Just a minor point... you mentioned planing the bottom off the plinth. Better to plane off the top edge as the bottom should be factory finished, and so water resistant. If you plane the bottom off any water that hits the plinth at the bottom will get into it and cause it to bubble....

Very good point - thanks for adding that

The way I ended up doing this, it looks like I won't need to plane them anyway, as the floor directly underneath the plinth now doesn't have any screed there - as I ended up applying masking tape to the plinth, put them back in place, added a bead of silicone under all edges of plinth, and then put the screed down. When it's finished drying, I'll take the plinth out again and lay the flooring down, with the vinyl planking "flowing" over the edge of the new screed, under where the the plinth will be placed back again - hopefully that will ensure the finish looks good.

If I do end up needing to plane the plinth because of the added height of the vinyl planks, then I will keep your point in mind and only plane off the top Glad you brought it up actually, as knowing me, I could very well have gone and planed the bottoms!

 

[dazlight]

Well done on the screed. Great screed stopgap 1200 pro, just got a pallet in.

 

[Shoganator]

Thanks dazlight

Well, I spent the whole of this evening after work putting down the vinyl planking. (Last night I put down the gerflor primer on top of the screed which had been down for about 30 hours prior).

Managed to finish everything. Just need to put the dishwasher back in place, and then sort out the plinth pieces. Here are the pics!

Primed with gerfloor primer:

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• Shoganator
• 23 Oct 2013
• 1

Vinyl planking1:

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• Shoganator
• 23 Oct 2013
• 1

Finished:

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• Shoganator
• 23 Oct 2013
• 1