The Content Of The Article:

Although friendly and warm, the traditional fireplace does not only have advantages. And when it does not serve, it's a real vacuum cleaner calories! One of the solutions is to close the roof exit by a hatch.

Install an open fireplace flue.

Necessary material

  • Bastard mortar (predosed)
  • Fastening resin
  • Chimney flue ("Ti 201" from Eurotrappe)
  • Dry sand (for the counterweight)
  • Black paint for high temperature
Thanks to Patrick Gaveau and Eurotrappe (59)

Difficulty: 3/4
Cost: from 800 € (according to configuration and constraint of the building site)
Time: 1/2 day (not drying the mortar
Equipment: trough, sponge, trowel, open end wrenches, male wrenches, pliers, flat chisel, perfoburineur, grinder...

A chimney evacuates fumes efficiently when it is able to create an ascending and permanent air flow. But once the outbreak is over, the calories in the room air continue to be drawn through the duct and the room cools down. To put an end to this phenomenon, various occultation devices have been invented: metal shutter closing the opening of the fireplace, hatch at the bottom of the duct or, as here, flap covering the stump.

Control the draft with a movable flap

This shutter is composed of two sheets of stainless steel compressing 30 mm of rockwool. The set is fixed at the top of a mast which goes up and down from a support resting on the stump. The opening and closing are actuated by a chain connected to a pulley and a counterweight, itself equipped with a return chain in the case where the shutter would be stuck by frost or blocked under the weight of a thick layer of snow. The open position can be adjusted to a height of 19.5 cm, which allows you to control the draft and reduce wood consumption. Finally, a safety chain retains the counterweight if its cable breaks.

Diagram of the operation of the hatch

Diagram of the chimney trap

1. Shutter
2. Mounting bracket
3. Pulley
4. Security chain
5. Comfort spring
6. Counterweight
7. Diamond tip
8. Recall chain
9. Opening adjustment chain

Effortless operation

For the mechanism to work properly, the counterweight must be adequately weighted (with sand): a simple pull on the flap must allow its descent. Then it must go up without intervention of the user.
Another condition for the maneuver is effortless: the support mechanism must be placed perfectly horizontal and centered with respect to the opening of the conduit.

Installation of the mechanism

Destroy the bricks of the pillars of the coronation chisel.

  • The bricks of the coronation pillars are unsealed at the chisel.
  • Be sure to hold fragments that could break tiles or fall into the duct...

Measure the width at the center of the duct opening.

  • Measure the width at the center of the duct opening.

Adjust the width of the mechanism bracket.

  • Then assemble the support of the mechanism that controls the flap and adjust its width according to the raised dimension.

Present the mechanism in its place.

  • Present the mechanism in its place.

Change the width of the orifice

  • Check that the fixing angles rest correctly on both sides of the opening of the duct.
  • If necessary, change the width of the orifice.

Center the support on the opening.

  • Lock the nuts of the support and center it on the opening.
  • Use one meter to check the front and back dimensions.
  • Post the locations of the holes to be drilled.

Check the horizontality of the support.

  • Raise the mast a few inches to slide a spirit level to control the horizontality of the support.

Drill the masonry of the chimney stump.

  • Drill the masonry of the stump: the holes (Ø 10 x 70 mm) being a little skew outwards.
  • In brick, do not use percussion.
  • Ankle then.

Replace the support and check its horizontality.

  • Replace the support, check its horizontality again.
  • In case of offset, compensate by sliding one or more washers in stainless steel under one of the angles.

Installation of the trap

Attach the return chain to the welded ring at the bottom of the counterweight.

  • Attach the return chain to the welded ring at the bottom of the counterweight.
  • To do this, use the quick link provided.
  • Tighten firmly with a wrench.

Load the sand counterweight.

  • To load the sand counterweight, follow the instructions in the manual.
  • Depending on the dimensions of the shutter, the required volume is indicated as free height (above the sand). Here: 10 cm.

Pass a strap at the top of the counterweight.

  • Pass a strap at the top of the counterweight.
  • Lower the return chain then the counterweight, cone down.
  • Block the free ends of the strap on the support.

Fix the operating cable at the top of the counterweight.

  • The counterweight retained by the strap, fix the maneuvering cable (passed in the pulley of the mast) at the top of the counterweight.
  • Then attach the security chain.

Pass the spring in the last link of the closing chain.

  • Pass the spring in the last link of the closing chain.

Attach the other end of the spring to the bottom of the mast.

  • Attach the other end of the spring to the bottom of the mast.
  • Release the strap.
  • The mast rises thanks to the counterweight.

Place the shutter in equilibrium at the top of the mast.

  • Place the flap in balance at the top of the mast and push it down.
  • The assembly must go up alone thanks to the counterweight.
  • If not, add sand.

Screw the flap underneath.

  • When balancing the counterweight is complete, screw the flap underneath using the four supplied stainless steel TF screws.
  • Tighten the screws, but without exaggeration.

Finishing of the coronation

Apply a primer that facilitates the attachment of bastard mortar.

  • Wet the edge of the opening.
  • It is possible to apply a primer which facilitates the attachment of the bastard mortar or to mix a fixing resin with the mixing water.

Spread the bastard mortar around the opening.

  • Spoil a few pounds bastard mortar in a trough and divide it over 2 cm thick. around the opening forming a slope leading the water outward.

Press the shutter so that it leaves the imprint of its outline in the still fresh mortar.

  • You do not have to completely fill each of the sides to go to the next step: press the shutter so that it leaves the imprint of its outline in the still fresh mortar.

Smooth the mortar sloped with a trowel.

  • Leave the shutter up to complete the application of the mortar.
  • Smooth it down with a trowel and then with a flatbed to obtain a more even surface.

End of flap assembly

Trow the location for the nail that will hold the chain.

  • Open shutter and chain slightly stretched, locate the location of the nail that will retain it.
  • We can modulate the draw by holding the chain by one of its links.

Form a loop with the chain to shorten it.

  • Shorten the return chain: only the last link must be able to hold on to the nail.
  • Form a loop and attach it using the supplied S-hook.

Handyman's tip

Paint the closing chain and its handle in black.

  • So that the closing chain and its handle are more discreet, they can be painted in black with a paint for high temperature.
  • Protect the fireplace masonry with cardboard.

Practical tip

Equip a harness to work at height.

  • Working at height requires respect for security rules. It is essential to equip a harness and a lifeline, to provide scaffolding or failing a roof ladder.


Video Instruction: How to Install a Chimney Liner and Damper - This Old House