Mantel over gas fire – plywood or solid
DavidHolmes | Posted in General Discussion on
Just finished my first cultured stone fireplace and have to install a mantel shelf. Haven’t done a lot of finish carpentry but find resources such as this generally have the right solution. Fireplace is 9ft long x 45″ high, insert sits at floor level and plan on building a mantel box 9″ high x 7″ deep with 10″ top shelf and finishing with mouldings. Stone face is 6″ from wall and extends into one corner so no return on box at that end.
This will be my first mantel and clients are thrilled with the stonework so want a similar result with the mantel.
- I have been cautioned re the heat and am considering 34″ birch veneer plywood to construct the box instead of 1″ oak. Have to locate 10 ft sheets as big box stores in Vancouver only carry 8 ft.
- Concerned that 9 ft length with open box at one end and heat will warp the face board and clients do not want the top shelf any deeper so not much room for back bracing
- Plan to build box with butt joint on return side with 1″sq fir backing insude corner, 2″ x2″ screwed to wall and glue nail top shelf to it. 1″ x 2″ cleats on corner wall to gluenail open end of box, crown moulding and edge moulding to hide plywood edges
Appreciate any advice or better solutions.
Replies
I have been cautioned re the heat..
I would put tile/stone on the faces of the wood facing the Fire!
But if fire is THAT HOT I tell the folks to invest in several fire extinguishers!
EDIT..
Sort of funnin ya.. If wood is offset from direct flame and heat I do not see a problem.. But just me...
I would tell then there is a limit to the amount of wood they can throw in the fire PIT!
Edited 3/21/2005 3:17 pm ET by Will George
I don't see any problem in using plywood for the mantel -- as long as there is adequate clearance (fireplace to mantel).
I have built maybe half dozen mantels over the years, but always to replace existing mantels, which I used as a guide for basic measurements.
If you are in doubt about clearance allowances, this kind of stuff is usually covered in building codes; you could either look it up in the book covering your area, or call the building department in your municipality.
David
As Nikkiwood suggested, check with code.
I've built over 100 mantles and there is a distance that the mantle has to be above the fire box, that distance is based on how far out(proud) the mantle will be from the stone/brick.
Doug
David,
I have built a few mantels in my day and usually the manufacture of the fireplace has clearance specs ,firebox to combustables , usually 45 degrees or less. if the mantel sticks out 12 inches then it needs to be 12 inches up.We usually build our mantels out of solid lumber lock mitered at the corners. Just plan for it to try and dry out. We have also used a sub box of timberstrand and glued it to the back of the finish material with construction adhesive when we wanted it to sound soild , might help the warping problem also ,as long as the solid lumber doesnt get to wide and cause movement issues.
Tim
Edited 3/21/2005 10:25 pm ET by Tim
I build mantels-mantles full time,and have always use hardwoods.
The reason is the finish carpenters use plys,mdf and whatever else the can come up with.
This is good for me because after a couple of years the home owner calls me for a real mantle and a major up grade.
Sheet material will let you down no mater what the code and clearance maybe.
Also I have used Deft Laq for years now with little or no problems.
Figure the cost of sheet than figure Hardwood and you will find very little difference in cost
The end look is night and day.Jimmy
http://www.creativemantels.com
Edited 3/21/2005 10:15 pm ET by Jimmy
Jimmy ,
I have to agree that solid wood is always the best bet . There just isnt enough wood thickness in plywood to keep up with all the fluctuations .
Tim
Many thanks for your replies - sorry I didn't acknowledge earlier but family emergency. The code clearance is not a problem - 3" overhang and 20" clearance. Solid wood recommendation now my plan and prompted me to talk to a couple of hardwood specialists locally. Found a piece of maple rough 3"x10"x120". They can get it planed to 2.5 x 9.5 and clients are a go.
Remember I am new to finish carpentry ( don't own a router and have only trimmed laminate - plan on buying a dewalt) but always ambitious to try something new. Here's my plan so shoot me down if I am heading for a crash and be patient with my terminology please!
Shelf will attach to wall with ledger approx 4" above top of cultured stone face.
Front of shelf will attach to 2" x 6" maple fascialintel. Latter will have 34" rabbit which will sit on front of stone which I have leveled and face will protrude 34" below horizontal level of stone.
Top shelf will cantilever 3" and simple covechamfer on edge. Clients like modern simple!
I will attach the 2" x 6" to the top shelf with a dado joint. Assume I can double rabbit the top of 2" x6" and cut a slot to fit in the underside of shelf - all without router table! 2" x 6" return will be mitered with 1" x1" backing to the joint.
May add crown moulding subject to clients review of initial assembly. Glue and screwnail. Finish will be stained.
Various materials will cost about $500 Canuck dollars and hope to finish in 3 weeks - just joking! 15 hours?
I don't want to have many nailsscrews in the top shelf or fascia. Thought of joining fascia to shelf with 1" x1" corner backing but dado appeals to me plus I get to use my new router!
What do you think?
Many thanks for your replies - sorry I didn't acknowledge earlier but family emergency. The code clearance is not a problem - 3" overhang and 20" clearance. Solid wood recommendation now my plan and prompted me to talk to a couple of hardwood specialists locally. Found a piece of maple rough 3"x10"x120". They can get it planed to 2.5 x 9.5 and clients are a go.
Remember I am new to finish carpentry ( don't own a router and have only trimmed laminate - plan on buying a dewalt) but always ambitious to try something new. Here's my plan so shoot me down if I am heading for a crash and be patient with my terminology please!
Shelf will attach to wall with ledger approx 4" above top of cultured stone face.
Front of shelf will attach to 2" x 6" maple fascialintel. Latter will have 34" rabbit which will sit on front of stone which I have leveled and face will protrude 34" below horizontal level of stone.
Top shelf will cantilever 3" and simple covechamfer on edge. Clients like modern simple!
I will attach the 2" x 6" to the top shelf with a dado joint. Assume I can double rabbit the top of 2" x6" and cut a slot to fit in the underside of shelf - all without router table! 2" x 6" return will be mitered with 1" x1" backing to the joint.
May add crown moulding subject to clients review of initial assembly. Glue and screwnail. Finish will be stained.
Various materials will cost about $500 Canuck dollars and hope to finish in 3 weeks - just joking! 15 hours?
I don't want to have many nailsscrews in the top shelf or fascia. Thought of joining fascia to shelf with 1" x1" corner backing but dado appeals to me plus I get to use my new router!
Enclosed jpeg. What do you think?
Hi David. That's one big piece of maple! I would consider changing a couple of things. The first is you mentioned returning the fascia piece but what about the top. You will see the end grain? Another concern would be expansion and contraction of the fascia. If it is attached solidly at the bottom edge then the top [double rabbit] must float. If it floats and contraction allows then the joint may open and show the shoulder of the tenon. I would either glue the top edge and have the bottom float or glue the bottom and not rabbet the top, but rather leave the full thickness into the bottom of the shelf. Another concern would be the exp. and con. of the top. Once again if it is attached solidly at the back then it will pull the front out of level with contraction or push it out of level with expansion. Just a couple of thoughts ..........Peter
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