Construction History

Construction History

Our light house was built in 1840, a period when lighthouses were being built all around the great lakes. Shipping was the major form of transport, and lighthouses were the only aids to navigation. In a time of GPS and cell phones it is difficult for us to imagine the problems encountered by those early settlers of Canada, who had to make the arduous trip without such luxuries. There were very few steam engines; the first steam boat that used a propeller was in built 1842, and the technology would take some time to become common. There were steam paddle boats before that but they were mostly river boats more applicable to calm waters, and would face problems on open waters.

When learning about the lighthouse, it helps to know something about navigation under sail; The prevailing wind is west which means that travelling from Toronto to Kingston was very easy, but the other way was a difficult trip. The only way to do it was to tack completely across the lake, which involved taking an angle directly at each shore before reversing. Ships could take two or three days tacking back and forth across the lake to make westward progress. Every approach to either shore was perilous especially at night or in bad weather and the lighthouse was their only way of knowing where they were.

Prince Edward County was particularly bad since tracking past Point Petre puts a sailing ship on a lee shore (a shore where wind pushes ships onto land). The Presqu’ile light was a safe harbour and an important positional point when tacking westward to Hamilton and Toronto from Kingston and Montreal.

Lighthouses were built mostly of stone but there were wooden ones as well. It was decided to build the Prequ’ile lighthouse out of stone. Local limestone was used even though there were recommendations to use Kingston limestone. There is a difference of opinion about the quality of local limestone. There are many other local buildings made of local stone and they are just fine. We don’t know the condition of the stone yet, but that is a part of the story that will be explained.

In those days the only mortar available was lime which was almost always made on site. Lime mortar is made by roasting limestone to make quick lime and then adding water, or slaking it, to make slaked lime. This is mixed with sand and forms mortar. The quality of the mortar is highly variable due to roasting temperatures, time of roasting and storage of the mortar. The type of sand is a factor of quality too and crushed rock sand was recommended, but was not used. In 1840, the availability of crushed rock sand at Presqu’isle probably made it very expensive or even unavailable. Crushed rock sand has sharp, pointy grains which make it very good for use in mortar as it digs into the mortar. Beach sand has round grains, which do not embed themselves as well, and makes mortar fall apart easier. The mortar used was not as good, but beach sand was widely available.

Within only two years of finishing the lighthouse it was leaking water and there is much discussion as to why. Local opinion has it that the stone was inferior but many suspect that the real problem was the mortar, and possibly the dressing (sanding, shaping) and fitting of the stone. Lime mortar is best when used in small quantities, which requires the stones to be dressed flat and square. A combination of poorly dressed and fitted stones and possibly poor quality mortar could be a more realistic reason for deterioration of the condition of the lighthouse, causing large gaps which are filled with weaker, permeable mortar.

The lighthouse is constructed with an inner wall and an outer wall with a rubble filled cavity between. Ideally the rubble would have been semi-fitted with mortar but we have no idea if mortar was used. One of the problems with lime mortar is that it is not waterproof, and over years, very slowly, it can wash out. We believe that the mortar began to wash out almost as soon as the lighthouse was built. It is an interesting historical note that the Romans had developed waterproof mortar but the knowledge had been lost and was not re-discovered till 1850 in England and was called Portland cement which is still in extensive use today.

As the years went by more and more mortar was washed out of the joins between the limestone blocks; and so cavities were forming inside the walls. These cavities filled with water and the action of frost started to further deteriorate the structure by exerting pressure in winter. By 1894, the condition of the lighthouse was considered critical and it was decided to surround the lighthouse top to bottom with very substantial timbers and iron hoops. These timbers and hoops would form a crib and hold the stone in place but would also provide a base for the addition of cedar shingles to keep out the rain. We have no record of who designed this but it worked very well and after 120+ years is still doing a fine job.

After 175 years; the lighthouse needs a little help. Luckily for the lighthouse, it has survived long enough to take advantage of some very modern methods and materials that can hopefully restore it to its’ original 1840 or 1894 condition. Options include the use of some very good grouts that can be pumped into the voids and even stainless steel ties that can be used to invisibly hold the stones together. Many old limestone buildings have been restored to their original splendor and it is our intention to make our lighthouse one of them.