Fixing a mantle piece top

[tom owens]

I,v been asked to machine a piece of timber up for a mantle piece top. The tops going to be sat on a brick fire surround. I want to be able to machine it and finish it in the shop.

How would anyone else fix it to avoid screwing it as i dont want to ruin the finish.

Pink Grip

 

[joiner_sim]

No-nails or pink grip I think is the way to go. Once the adhesive has set it won't budge!

 

[woodbloke]

I fixed an oak top to a natural stone fire surround by putting in some (say hafl a doz) brass screws on the underside and leaving around 8mm showing for a 'key' and then setting the whole thing on a bed of cement. Easy then with a small tapometer and spirit level to get the thing dead plumb - Rob

 

[softtop]

When fitting marble fireplaces you normally set the top into the wall, so it is cantilevered from the wall and that (plus a bit of Gripfill) will keep in in place. Don't know if it's practical to chisel out the wall though...

 

[chris_d]

If it was going in my house and assuming that the mantle is >50mm thick then I'd do as follows:

1. Drill four 10mm diameter blind holes, 25mm deep, in the underside of the mantle, two per brick support along the plane perpendicular to that of the mantle.

2. Resin fix 8mm diameter threaded steel rods (stainless if mantle is oak) into the holes in the underside of the mantle. Rod length to be at least 75mm.

3. Place mantle on brick supports and mark exact locations of rods. Drill 10mm diameter holes in supports to suit actual rod lengths.

4. Resin fix rods in brick supports using temporary wedges/packers to keep the mantle level.

Now, if your mantle isn't oak then you could use a "machine thread to wood thread" screw instead of threaded rod eg screwfix part number 11850-12 but that may also depend on the thickness of your mantle. I always keep some threaded rod in stock including resin since you can make all manner of repairs with minimum fuss.

HTH,
C

 

[walshy2]

I would go down the cantilevered route and use grip fill I think this was already mentioned but I have used this before and it has work for me.

 

[AndyT]

The traditional method is to fix it before plastering the wall. Use mirror plates screwed into the back edge, screwed through into the brickwork, with the screws and plates being hidden when the plastering is done. You could get the same effect by hacking out plaster along the length of the shelf and around the plates.

Gripfill's probably easier!

 

[Eric The Viking]

Slightly at a tangent: If it's heavy timber, I'd be tempted to get the rough sawn piece really warm in the house before finally machining it: over a mantel it's going to get pretty warm in the centre and it's bound to move around a bit.

On fixing, I'd go with the consensus: Grip-fix or No More Nails. It works really well in that sort of application. If you use mirror plates, use brass screws, otherwise any trace of damp later will 'pop' the plaster as either the screws or the plate rust. Flues usually get fairly damp in the summer and early autumn when fires aren't lit.

 

[tom owens]

Funny steel rods should be mentioned because i thought about 6 steel dowels as fixing points but then thought it was a bit ott. Its an old fire surround and the fire wont be getting used, Its more of a show piece. The timber is just pine 1800x60x260mm.

 

[GazPal]

You could consider dotting and dabbing the mantle with NoNails and simply lay it in place and level - using packers/a spacing strip if the mantle tends to slump and/or to maintain an even bed. Once the NoNails has cured, apply a fine mortar joint - using a suitable jointing tool - between mantle and brickwork and the job is done. :wink:

Mortar cleanup via damp sponge.

The old means of securely fitting mantles to brickwork is to fit fish-tailed dog/framing ties to the underside of the mantle before bedding it on mortar, with the ties able to slot into vertical (Mortar filled) brick perpends. The other alternative is to apply screws to the mantle underside and lay on a bed of mortar.

A strip or two of expamet fixed to the underside of the mantle helps adhesion between timber and mortar.

Whenever possible, allow timber to acclimatise to it's new home before tooling.