As many of our visitors will be aware the Portico at Annesbrook has been in need of repair for a number of years. We are delighted to announce that in the next couple of weeks it will be restored back to full working order.
The Portico was allegedly designed by Francis Johnson who also designed the GPO in Dublin. It was built on to a 15th century farm house, part of which still remains.
The restoration of the Portico is part of our on going commitment to restoring the house back to it’s former glory. Our built heritage is of great importance to us all and we would like to thank you for your support and look forward to you all enjoying the unique atmosphere of Annesbrook in the future.
A short history of the portico & restoration
The portico erected in 1821 on the façade of Annesbrook in anticipation of a visit by George IV, then the Prince Regent, is crumbling. The Ardbraccan limestone from which it is constructed is deteriorating after some 200 years due to salt crystallisation. This is an effect where the formation of salt crystals in the pore cavities of the stone causes it to burst. Repeated wetting and drying of the stone results in the weakening of susceptible layers of stone, which becomes evident by fractures, fissure or cracks, and a general friable surface.
There is evidence to show that the portico was hastily built which caused some early settlement and which added to its woes.
Traditionally repairs would involve the replacing of decayed and damaged stones which would be a prohibitively costly endeavor. New technology is now available which essentially replaces the lost binding compound with a natural silica gel and which re-establishes the stone fabric to its original state. This is achieved by applying a special formulated solvent-free stone strengthener with a silicic acid ethyl ester base which reacts with the water stored in the pore system of the stone. During the reaction process amorphous and hydrous silicon dioxide (SiOs or Silica gel) is deposited as a binder which replaces the original binder lost through weathering.
The real value of this process is that it provides future protection to the existing stone work, avoiding replacement and thus avoids loss of patrimony. It can also be done at a small fraction of the cost of a rebuild with new stone replacement. This is an ideal example where high technology can come to the aid of conservation and provide cost effective protection to our built heritage.