Cornice boards and Lambrequins save on heating costs

Several years ago our Public Service company sent out a flyer attached to their bill showing a picture of a cornice board with a dust cover.  They said the dust cover (the top board on the cornice) prevented air circulation behind the drapes and thus prevented drafts around your windows.  A further reduction in airflow could be achieved with the use of a Lambrequin which has side pieces that can extend to the bottom of your window sill or even to the floor.

An arched top cornice with brass tacks

    We have been given a work order for an arched top cornice with a shaped bottom and brass tacks outlining the shape.  Sometimes our work orders are not drawn to scale and the finished shape cannot look exactly like the rough drawing.  In this example the required width is about twice what the drawing would indicate so the curves are much less pronounced.  Once again we will use Homasote for our shaped top since it is relatively inexpensive and relatively easy to bend.  After the box is built and polyester batting applied over the plywood we will cover it with muslin before applying the finish fabric because with most shapes it simply produces a better looking product.   Since the pattern in this fabric is quite detailed and has many lines to match we will sew it from the back side making sure all the lines meet.  The seam from the front is not quite as good as a regular seam but much better than having lines that don’t match which makes the seams much more obvious.  We lay the sewn fabric on the covered box and mark the part of the pattern we want to be centered top to bottom and side to side.  Then we make minor adjustments and mark the parts of the pattern that will be at the points of the bottom shape to give the best overall balanced look.  After pinning the fabric in place we measure down from the top to a similar part of the pattern on each side of the cornice.  Then we lay a straightedge across the pattern and make minute adujustments so that pattern is exactly straight across.  Now we start the stapling process.  First we make  cuts where needed and staple the bottom edge.  Next we flip the board over and staple the back edge of the returns.  Then we stand the board up on its bottom edge and staple the the back edge of the top board.  Since we don’t know if the shank of the tacks will protrude through the face board we leave the inside lining for last.

    At this point we flip the board face up and lay the tacks an inch above the bottom edge to see how many tacks we need for each scallop.  We start by hammering in a tack at the top of each point and at the outer ends of the face.   Then  we can hammer in the tacks between the points.  Some of the tacks may need to be pulled out and hammered back in if they are a little out of position.  After the tacks are all hammered in we flip the board over and apply lining and gimp to the inside to complete the cornice.

Covering the lip of a rope welt

Apply 3/4″ Millennium tape to the wrong side of the fabric and press it down to make a sharp creaseimg0001.jpgHot glue the folded fabric to the rope welt lip  

   After we have hot glued rope welt to the edge of the cornice we need to cover the exposed lip of the cord.  The easiest no-sew way to do this is to make a sharp crease in the fabric by pressing it together with our fingers using 3/4″ Millennium tape.

Matching those pesky stripes

The finished corniceThe back side of the fabric with masking tape applied to keep the foot from getting stuck under the bulky threads of the stripesThe finished seam from the front

   Every once in a while someone will give me a workroom tip that saves a lot of frustration and results in a much nicer finished product.  This suggestion came from Catherine who managed one of the Calico Corners stores and her suggestion involves matching horizontal stripes on a cornice board .  Even with a walking foot sewing machine it is sometimes difficult to match all the horizontal stripes without tearing the seam apart over and over again.  The matching is not so critical on soft treatments like valances and drapes because of the folds in the fabric.  But on a cornice board the fabric is stretched tight and shows every imperfect match.

   We begin by pressing down about an inch and a half of the edge of the fabric to a place where the matching would give the most pleasing appearance.   Today’s fabric is a little difficult because of the bulky threads that make up the stripes.  So after pressing we lay a piece of masking tape to within a quarter inch of where we will sew.  Next we match the two pieces of fabric and begin sewing as close to the edge as possible (perhaps less than 1/16th inch).  As we work our way down the seam we can make very small adjustments at each stripe to make sure they match.   Pull off the masking tape before applying the fabric over the batting on the cornice board.

Let’s make a mock roman shade cornice board

Make plywood box, attach batting, cover with muslin and mark lines 2 3/4″ apartSee if Millennium tape will stick to this fabric.  It doesn’t because of a teflon coating so we will use glue.Glue folds with fringe adhesive so they lay perfectly straightLay out center foldLay out the top and bottom foldsSee how the folds look on the corniceGlue on the strip of fabric that covers the bottom edge and then continue attaching the foldsWrap the folds around to the inside of the returnsUse cardboard tack strip to position liningStaple lining in placeFinished !!    To make a mock roman shade cornice board with matching pattern we first staple batting to the plywood box and cover the batting with muslin.  On this board which is 8 1/4″ high we want three folds so mark the muslin with lines 2 3/4″ apart.  Now let’s lay out the fabric loosely to see which part of the  pattern we want centered and begin by laying out the center fold.  Now we will lay out the top and bottom folds to match the pattern of the center fold and start cutting the fabric.   After the pieces are cut we try Millennium tape to see if it will stick and it won’t (probably a teflon coating on this fabric) so we use fringe adhesive to glue the folded fabric together.  This will keep the fold perfectly straight when it is applied to the cornice board. 

    We first apply the piece of fabric that will wrap around the bottom edge and then  the three folds making sure they are each 2 3/4″  and the pattern of each fold matches above and below.   The folds are wrapped around the inside of the returns and a lining fabric is attached using cardboard tack strip and staples.  Now stand it up on its bottom edge to make sure the folds hang evenly and we are finished.

Butting two cornices together in a corner

The wiggle room on the left dust cover allows us to draw the two pieces together so no light peeps through the jointRight side board butts tightly against the dust cover of the left side board

  When we are making a corner cornice where two boards come together and wrap around the corner with no returns the most effective joint will not allow any light to peep through.  If the measurements from the corner to as far out as you want the cornice to go are 125″ on the left side and 72″ on the right side we will make the top board (dust cover) 124 1/4″ because it fits inside the left return which is 1/2″ wide plywood and we want a little wiggle room (1/4″) on the right end.  The dust cover on the right side board is the same size as the face board minus 1/2″ because it fits inside the right return.  How do we figure the size of the face boards?  If you look at the photos you will see that the right side board butts up against the dust cover  of the left side board.  Let’s say we have 6″ returns so our dust cover board is 5 1/2″ wide.  If the customer wants the right side cornice to extend 72″ from the corner we would make the face board 72″-5 1/2″ = 66 1/2″.  The face board on the left  side will but up against the finished face of the right side which is 6″ deep.  With the left side measure 125″ from corner to outside left return we will make the face board 125″-6″= 119″.  Notice from the photos there is about 1/4″ between the inside end of the left side dust cover and the wall at the corner.  This is the ‘wiggle room’ we need so the joint is nice and tight.

Edge joining plywood to make a long cornice board strong

The finished cornice board is very stiff even though very longedge-joining-plywood-2127.jpgStaple the boards together with alternating joints and then hammer in ‘dog ears’

   When interior designers ask us to build upholstered cornice boards that are over 110″ long we need a way to make them strong so they won’t break while being transported to the customer’s home.  Plywood comes in 96″ long sheets so if we have an order for a cornice board 185″ long and 12″ high we could just edge join two boards-one 96″x12″ board to another board 89″x12″  with a joint roughly in the center.  But that would be the weakest point of the board if two people each lifted an end.  A much stronger solution is to cut five boards 2@96″x6″, 2@ 44.5″x6″ and one at 89″x6″.  The two 44.5″ pieces would be attached at each end of a 96″ piece producing a board 185″x6″ and this would be used for the bottom half of the face.  The other 96″ piece would be joined to the 89″ piece producing another 185″x6″ piece which would be used for the top half of the face.  Then the two 6″ sections would be joined together to make a 185″x12″ board.   Most cornice boards have a dust cap or top board that lays on L-brackets for when the cornice is installed.  The joint(s) in the dust cap boards would be located at least a foot away from the joints in the top face board.   By alternating our joints this way we can build cornice boards up to 20 feet long with very little loss of strength. 

   The five boards are laid out on a table to make sure we have made the bottom three  6″ boards the same length as the top two 6″ boards.  Next we measure to make sure they add up to 185″.  There is a good old saying “measure twice and cut once”.  When we are sure the five boards will make one board 185″x12″ we lay a long straightedge on top of the boards at the long edge to make sure the joined boards will be nice and straight (we can’t just assume we made  perfect 90 degree cuts so the straightedge shows us where we have to adjust the lineup).  We will first staple all the boards together on one side, then flip the whole thing over and staple them together on the other side.  Then we hammer in aluminum edge joiners (dog ears) every two to three feet along the horizontal middle joint and spaced every two to three inches along the vertical joints since these joints will have the most stress.