Reducing size of fireplace builders opening

With a stud partition instead, if you don't intend to install a fire.

If you are installing some sort of fire, then I'd use a concrete lintel.

Christian.

Andy, as said above, if you are putting a fire back in then use a lintel. These even have the correct angle for the draughting made into them.

When I moved into my first house, the EXPERTS, had manufactured their own lintel as it was a through the wall type fire place serving two rooms. They made the angle so shallow that 49% of the smoke went into one room, 49% went into the other and only 2% went up the chimney. Luckily the seller was able to with-hold a final payment to said EXPERTS and gave it to me to get the job done correctly.

The internal angle for correct draughting is about 43 degrees. I was able to find it in a book in the library. Probably on the Net now.

Chris.

.........have a look here...

Here's one I did earlier:

fireplace04 and fireplace11

Mark S.

Andy, have you looked here for general chimney building............

Chris.

Thanks for the replies everyone. Looking at my original post I failed to mention that the replacement we are looking at is an inset gas fire.

With this in mind I am not sure whether I need to use a throat forming lintel or standard concrete one.

I will check the position of the vent from the fire. If it doesn't clear the depth of a standard lintel I will fit a throat forming one.

Andy.