How to fix pieces of MDF on landing

[Ellsa100]

Hi there

We relocated our staircase opening when we had a new staircase installed.

The new staircase opening meant we removed a newel post where the old opening was and put a continuous banister in its place. The problem is where the newel post was originally located, the builders installed (what I think is) some MDF trim to cover the gap but this new MDF trim isn't flush with the rest of the trim underneath the banister. The new MDF trim naturally flexs outwards, which I think is the main reason for it not being flush. If I push on the middle of this new MDF trim it seems to become flush. See picture below, where you can see where a bump on one side and a large crack on the other side of this small piece of MDF trim.

We have fallen out with the builder so I can't get them to repair. I want to fix it myself.

Any suggestions on the best way to do it? Also, while I think it is MDF, I guess it could be plasterboard. Would any solution be different depending on whether it is MDF vs plasterboard?

I had a few ideas:
1. Remove this small piece of MDF, install say three wooden batons behind the MDF trim and re-attach the MDF to that. If the MDF is secured to a baton in the middle it should stop the MDF flexing outwards; or
2. Simply sanding the small piece of MDF in situ so it becomes flush with the rest; or
3. Use a nail gun to secure the small piece of MDF more securely to the other MDF try to stop the outward flex.

I'll then need to fill, sand and re-paint the whole thing.

#1 seems the most sensible. #2 seems like it will be a lot of sanding, plus there will still be flex in the small MDF piece. #3 I think will be tricky to get good fixings to the abutting MDF because of the angle and thickness of the MDF.

Thoughts? Suggestions?

Thank you

I

 

[Wayners]

Stick a small screwdriver in the crack.
Plasterboard it takes about 10 second to push it through.
You won't push it through MDF.

If it is plasterboard ( I think it is) get a strong magnet to find the drywall screws.
You may have them on that crack so add more to pull in.
Then we need to fill and make good.

See what you find first

 

[Ellsa100]

Thanks for your help.

I tried your suggestion of a (small flathead) screwdriver in the crack. It wouldn't push through. I did it in a couple of places - you can see the damage in the first pic below. Think the damage suggests MDF?

Also I was able to locate some photos I took at the time of the building work (18 months ago or so). In the second photo you can see the gap where this material was placed. In the third photo you can see the builder's original fudge, which shows them putting a strip of plaster board above the original (what I think is MDF) surface so that it appeared all flush. So I'm fairly certain this is MDF?

Thoughts?

 

[Tigercubrider]

That looks like plasterboard to me?
If it creates grey dust then it is.
If it’s MDF, then simply pushing it back in place will put it under tension as it would appear to be too big for the gap and needs a tiny bit removed off it’s length.
You could use an oscillating cutter on the seam to widen the gap and make room for it? Protect the “good” but by temporarily nailing a bit of wood on the good edge as a guide.

 

[Ellsa100]

I think my photos were a bit misleading - the grey board in the final photo - which I think was plasterboard - was removed as I told the builders at the time the edge looked too wide versus the edging around the rest of the landing.

 

[Wayners]

Pull strip of MDF out.
Put some wood where the bule lines are.
Fix old or new MDF back in with Stixall or similar.
Maybe a couple of screws. Drill MDF holes for screws bigger than screw so they don't bite. That way the MDF will pull tight.
Lots of wood glue on MDF edges

 

[Ellsa100]

thanks - I'll try this (and is basically in line with what i was thinking) and let you know how I get on!

 

[robinbanks]

Lots of wood glue on MDF edges

The only thing I'd caution with this; maybe avoid a water based glue - if there is too much water in it it can cause the MDF fibres to expand, making the edge curl. Consider a non water based glue or be prepared to sand and finish the gap