Limestone Fireplaces for Solid Fuel

With the great popularity of limestone fireplaces in recent times, especially the very attractive, but relatively soft limestone’s from Portugal, Spain and Turkey, many purchasers and potential purchasers have tended to ignore what type of fire can best be used with these fireplaces.

Gas and electric fires usually present little problem with most types of limestone fireplaces, but solid fuel (real fires) most certainly do. Don’t panic though! With correct alterations, adaptation’s and installation, most types of limestone fireplaces can be used with solid fuel.

Your problems start with your hearth. If this is a limestone hearth matching your fireplace, and is also in just one piece, then you have two problems to solve.

Firstly, the limestone hearth will crack from the hot spotting heat of a real fire. The area of the limestone hearth closest to the real fire will become exceptionally hot, whilst the far edges of the limestone fireplace hearth will be relatively cool. This sets up severe stresses in the limestone, and one day a crack is virtually guaranteed.

You can get over this problem however, by having your limestone fireplace hearth slabbed and sectioned for real fire use. This entails your limestone hearth being cut into three or possibly four pieces, and then reassembled with joins, these joins act as expansion joints and the hearth will usually also be backed by high temperature cement for extra protection.
The joints in the hearth now should prevent the stress spreading across the surface and therefore preventing a crack. A heat plate (the fourth section) will also assist in protecting the limestone from the heat and scratches.

The other problem with your limestone hearth is that it’s not very hard, light in colour and is relatively opened pored Real fires though, are dirty, shovels or ash cans must be used to clear the ashes, coal and logs inevitably spill onto your beautiful hearth. All in all, your limestone fireplace hearth may take a pounding, ending up badly scratched and very dirty. This problem can to a great degree be solved by the heat plate. This heat plate should be in a very hard stone such as granite, which does not scratch easily.
The remainder of your limestone hearth should be chemically treated with one of the latest super sealers.

You can then simply sponge off any dirt and keep your hearth and limestone fireplace looking good.

There could still be more problems for your limestone fireplace caused by the extra heat a real fire and solid fuel could cause. Your Limestone fireplaces back panel or slips, are also in very close proximity to the fire and will require slabbing and jointing in three pieces, backed by high temperature cement as an extra protection.

Another point to consider with limestone fireplaces and real fires is that most lime stones will show burn and scorch marks, if a real fire flame plays upon the surface of the limestone. or indeed, if the limestone surface temperature goes above around 400c...
These scorch or burn marks are permanent, so care must taken to insure that the flames do not burn the limestone or that the surface doesn’t get too hot.

Don’t be put off using a limestone fireplace with solid fuel, overall it performs very well as long as you take the right precautions.

Limestone fireplaces have been used for centuries with solid fuel fires in them so they truly do stand the test of time!

Alan Bottomley, 6th March 2008