Mary Lawson of Institute of Clay Technology Scotland branch talks history

Materials World magazine
7 Aug 2019

The former president shares experiences testing brick and concrete absorbency, and life just after the marriage bar.

How did you start working in the heavy clay industry?

I was employed in the Engineering Division of the BBC from 1941-1945, and my position concluded at the end of World War II. At that time, one was told where to work by the Central Register for Graduates. I was directed to apply to the Department of Scientific and Industrial Research (DSIR), an organisation set up after World War I to carry out scientific and development work needed by government. I worked at the Building Research Station (BRS), located at Garston, UK, whose scientific remit was to include every aspect of construction engineering. My first position was a scientific officer and the laboratory director was Sir Frederick Lee, who had worked with the Bureau of Standards in the USA on the Hoover Dam. I remained in full employment until retirement at the grade of Principal Scientific Officer in 1980.

Tell me about your move to Scotland

In 1949, it was decided to set up a sub-branch of BRS, to be located in the first Scottish new town of East Kilbride. I applied for transfer and pioneered setting up the BRS Scotland Laboratory (BRS Scot Lab) that year. I was to be in charge of the section dealing with all the basic construction units, clay and concrete bricks and blocks, natural stones, pipes and tiles, which included testing the raw materials, the finished product, and performance in use.

What did the lab discover?

Scotland used waste material brought to the surface with coal as part of the coal mining industry. Its advantage was that it was self-firing in the Hoffman continuous kilns. The geological deposits of the mineral clay in Scotland are a widely variable source material for a huge variety of products, including specialist medical components, fine china, down to the heavy clay section, for facing bricks to drain pipes and sewers. Compared to England, Scotland has a patchwork of complex geological systems. There are volcanics, a great glass on Edinburgh plain and sedimentary deposits. You do not have the huge deposits you have at Stoke-on-Trent. Clay deposits in the UK have characteristic features and are spread over several regions such as the Fletton clays of the Peterborough area and marls clays of the Stoke area.

What testing did you do of the materials in Scotland?

Bricks in Scotland were made from bings – colliery shale that came up from the coal mines. That material was self-burning because it had enough coal left in it. BRS Scot Lab sampled and tested bricks from 46 works between 1950–1965. On average the bricks were fairly low in soluble salts, Class 4 to Class 7 at 28-50 newtons per square millimetre (N/mm²), were durable – especially the vitrified black cores, and big at 24 x 7.6cm. Kiln control, or lack of, produced wide variability. One notorious batch of 10 bricks ranged from 25-84N/mm².

Bricks were laid, stretcher bond, overhand from the inside, a method not suitable for fair-facing the outer leaf, and vertical joints were left unfilled to provide rendering key. Rendering, or harling, was used even on 17th Century stone to increase the weather resistance of units and joints, aided by roof and window details designed for adverse climates. Rendered common shale bricks provided cheap and durable walling in hectares of Scottish suburbs for decades.

It was only when facing bricks became popular that problems came to light, because without the protective renders, we got rain penetration. As part of our research, I had rain gauges on buildings up to 30 storeys high. A rain gauge was outside the building, but the pipe came into a measuring device inside. There was 91 litres per minute of wind-driven rain going down per 83cm² – a square yard – of those buildings.

With the wind blowing, any crack or gap allowed rain penetration. The new popularity of cavity fill for insulation meant the cavity wall no longer protected against dampness. A lot of the high rises were soaking wet on the inside because of the water. Wherever the concrete floor came to the outer leaf, water would go in at that point, run along the concrete floor and go down the light fittings.

In one test I did, I took a wall panel, put it in a tank and boiled it until I could get maximum saturation to see just how wet a wall could be. I then dried it out and subjected it to driving rain. I found the driving rain only went 5–7.6cm into the brick work, but shot along both the joints to the inside.

A post-war government push for more houses and other corporate financial incentives for completing the biggest area seemed to influence outcomes. Large panel, precast concrete construction became popular, inspired by the success of such construction in Sweden. The issue, particularly for Scotland, was erecting the panels required tower cranes. For one third of the year in Scotland, the wind speed is above 30 knots, which was the health and safety limit for operating a tower crane. So for a great part of the winter, panels were made and piled up on a building site. By the time the panels were put into position, they were soaked. It was information like this that was shared with our station, plus a European committee I was involved in that looked at rain penetration.

How have you contributed to the Institute of Clay Technology association (ICTa)?

I was especially interested in brick production in Scotland where the raw materials used were very different from the rest of the UK. I fed this knowledge back to the main BRS at Garston. As a result, on retirement from BRS Scot Lab, I was delighted to be asked by the Scottish brick industry to supply them with any advice I may be able to give.

It was then that I became a member of the Scottish Branch of the Institute of Clay Technology [now ICTa]. ICT’s predecessor, the National Association of Clayworks Managers, was formed in 1927. The group evolved as the industry changed and allowed a place where those in the field could share their knowledge.

On 14 May 1981, I was honoured to be chosen as chairman of the Scottish branch as the first female to hold such a position in an ICT branch. Thus, I had a place on the main council of the ICT and attended periodic meetings at the headquarters, and was given life membership, which has continued with me into
ICTa and IOM3.

I attended all the annual and international conferences until I was in my late eighties, knew many of the members and became friends with them and their wives. I was at the 1993 conference and was staggered to be presented with the Ernest Simpson Award - the most prestigious award. The Immediate Past President at the time, Gwilym Lloyd, spoke about my long association with the Scottish branch and years of work on behalf of the brick industry.

How did you find being a woman affected you in industry?

The marriage bar was in effect until 1946. At the time, if you were a teacher or civil servant, you had to resign immediately on marriage. Such people were given a dowry, something like a month’s salary for every year they had worked. I was married in December 1946 so I just missed the marriage bar.

Prior to the transfer to Scotland in 1949, I was told married members of the civil service would get a house with the job in the new town of East Kilbride. So, the Executive Officer went to the DSIR headquarters to see if this applied to both women and men and they couldn’t find any reason why, if I was married, I shouldn’t get the house.

I got my house, and there were a lot of awkward feelings about it. There were people in similar situations who, as they were married before that time, were quite cross as they did not have the same opportunity that we did.

When I fell pregnant for the first time, I told my manager I would continue working as I wanted to keep my house, which was tied to my job. At the same time, an assistant who had just finished his national service told me about a woman he was courting who had been trained to look after children and was looking for work near East Kilbride.

What support did you get from your employer during that time?

There was no maternity leave or other similar support. You had six weeks’ paid sick leave and the establishment by the London end said, ‘I’m afraid you’ll just have to use those paid sick leave for your maternity’. I worked right up to the day before my daughter was born. When the five and three quarter weeks were up, I started work again and the girl I had been recommended looked after my daughter.

Every new director we got was assured that I would give up soon. Well, three more children and another 12 years later and I was still in it. As a result, I never got promoted. I worked for my career and finished up as a principal scientific officer when they discovered that they couldn’t do without me.

I have a great pension now because I worked 40 years complete without a break. But for all that time I made no profit because I was paying to renew myself, for others to look after my children and do the housework, the superannuation and income tax.

You attended the International Women in Engineering Day conference at the Institute’s London office in late June. What was that like for you?

Attending the conference gave me great pleasure. It reminded me of those happy years spent associated with an industry for which I had great respect and which did not seem to be aware that I was a woman, but just a colleague.