Filling hole in kitchen worktop

[JoeJoe]

Had my boiler has recently been relocated from the utility room, and I am now left with a 6cm x 25cm cut out in the worktop where the pipes used to pass through.

It is a standard chipboard laminated worktop, L-shaped (mitred). As it is in an almost invisible position, and will probably have a microwave sitting on top on the cut out, I am quite happy to keep it, as long as I can fill the hole somehow. The cut out is against the wall, and I will tile to it once the hole is filled.

I am looking for a hard, preferably light in colour, water-resistant surface.

Best I could come up with is to screw and glue a scrap piece of wood to cover the hole, leaving a few millimetres gap at the top, and them fill with wood filler to the surface of the worktop. If possible varnish the top of the filler.

Will it work? Any better ideas?

TIA.

[Martin Brown]

Do you have any offcuts of the original worksurface material or able to find something close enough in B&Q patterned edging tape?

What surface finish are you aiming for?

I'd probably be inclined to use a pigmented and filled acrylic polymer resin liquid cast to get the top surface to match and watertight seal. They sell something like it for filling in joints. Not ideal if it will be under load but should be OK in a dark corner.

If time was no object I might even craft a piece of wood to be an exact match after tapering the hole slightly to stop it falling through. Things are easier if you have access to the underside.

[JoeJoe]

Haven't thought of that...

Just done it and it worked a treat! Will give it a coat of varnish once glue is dry for water resistance.

Many thanks again!

[Brian Gaff]

I'd be worried if there is any likelihood of damp getting in and doing untold things to the material, but if nothing has happened thus far, I'd imagine your idea would be fine.

Brian

[JoeJoe]

Sink is at opposite end of the room, and I cannot envisage it ever facing more than a quick wipe with a damp cloth. The plan is for the microwave to sit on top of it.

[Ian Jackson]

Wood hardener (plenty of it) is good for waterproofing the edges of absorbent materials like chipboard. Slosh it on until it's saturated.

[stuart noble]

Why bother if it's nowhere near a source of water? I'd whack a piece of contiboard (or whatever melamine faced stuff I had lying about) in there, mainly to give a level, wipe down surface. Set it in the hole with body filler

[snot]

Covered with a microwave? There's your answer. Put the microwave on top of the hole and forget about it. Simples.

[Dave Liquorice]

Microwaves produce quite large quantities of warm moist air. Depending on where that flows you could get condensation forming. I'd make sure the edge of the worktop is well sealed at least along the top edge if filling the hole with something, which is proably adviseable or you will get warm moist air into the void or cupboard below...

[JoeJoe]

Managed to cut a piece of wood to fit very tightly. Put plenty of PVA glue + a couple of screws, so completely sealed around it. For good measure varnished the top, and it looks really good (colou doesn't match, but I really don't mind that.