Cementing in a gap over a fireplace for engineered flooring. Help, advice, information, answers and tips on all types of flooring from laminate and carpet to timber and vinyl

[EternallyLearning]

Hi. Very limited experience here. I recently paid someone to put down new boards and joists due to damp. They left it like this over the old fireplace block.

I'd expected him to board over it. I don't know if that's a normal way to leave it or not. The block is a bit uneven on top and the boards are 2cm thick so I guess it may have bulged up a little in places (not by much, though).

I want to put engineered wood flooring in this room. Obviously I need something to fill this space up to the same level of the rest. He says it needs cementing in.

Is that right, what sort of cement do I use and how long does it need before I can board over it? Is there any period of time I need to leave to let moisture get fully out is what I'm thinking. And when it comes to cementing it in, do I just seal that gap under the skirting with caulk or something and then pour the concrete into the space and smooth it down with one of those flat things afterwards? Or is there more to it?

And while I'm asking questions, do the skirting boards need to come off? I know there's space needed around boards to allow for expansion but there's no space for them to fit under the skirting. Does that mean it has to come off and then be put back on on top of the engineered flooring so that there can be a non-visible gap for expansion?

Any answers at all would be really appreciated. I am very new at this.

[stoneyboy]

Hi eternallylearning,
The reason for the lack of boards over the hearth slab could be twofold. 1. They thought you were going to install a fire and 2. Hearths generally do not have DPMs in them and rising damp would cause problems with wood floorboards. You will have to get advice, about rising damp, from the wood floor installer
Fill the hearth gap with self-levelling compound and leave to dry as per manufacturers instructions.
The cheap and easy solution for the perimeter treatment is to fit scotia moulding, pinned to the skirting to hide the expansion gap. It looks much better (but costs more) if the skirtings are removed and these are refitted covering the expansion gap.
Regards S