Oct 12th, 2014
This time I will be dealing with the Dry Stone Walling Association’s Intermediate Certificate. The Intermediate Certificate or level two, as it is some times known, is the first professional qualification in the DSWA’s craftsman certification scheme. The Initial Certificate, as explained in my previous posting, is the entry level qualification and is designed to introduce candidates to the scheme and hopefully encourage them to pursue the higher levels of certification as time goes by and they attain the relevant skills necessary at each level. In my opinion the Intermediate test taken in the context of its position within the craftsman certification scheme is probably one of the toughest DSWA certificates to attain. The jump from Initial to Intermediate is a long way requiring a number of new skills and techniques and indeed a different approach. The DSWA Intermediate Certificate comprises of two and a half square metres of wall including a wall head, this feature is the standard way of terminating a wall at a gateway or other break in a wall line. The wall head or cheek end has many different regional names but its construction is usually along the same lines and it is the first and most important feature a dry stone waller should learn how to build correctly, as many of the techniques used will be employed later in more complex features.
When one studies the marking schedule for the Intermediate Certificate it is immediately obvious where the priorities lie due to the allocation of marks. There are thirty marks available for the wall head element of the test and there are also marks available for batter and camber as well as line and straightness, fifteen points and ten points respectively. The wall head is obviously the most important element of the test and therefore I will deal with this first. When stripping out or dismantling the wall care should be taken to keep all the wall head stones separate to the building stone, this can be done by laying them out in front of where the wall head is to be built. Be careful to lay them out and not throw them as it would be careless to break one and therefore increasing the difficulty of the rebuild before you have even begun. It is very important not to dismantle the wall head in such a way that it can be reassembled exactly as it came down, this is making the assumption that the previous waller built that section of wall correctly, you may well be able to improve on his effort. The examiners will certainly prefer to see your interpretation of the available stone.
The most important task before starting to build the wall head is to set out the wall head by erecting a frame or profile of some sort; it is surprising how many candidates are unable to perform this task satisfactorily. If a frame is to be used you will obviously need to know the dimensions of the wall before the test day to enable you to construct a frame beforehand. I always prefer to have the frame tight up to the wall head; if it is set vertically it will act as a guide and the resulting wall head should also be vertical. Some wallers prefer to have the frames set away from the wall head as it allows more access to the face of the wall head but this necessitates the use of a spirit level which in my opinion is just introducing something else that can go wrong. It can be quite difficult to get an accurate reading with a spirit level from an uneven surface on a stone. Use the inside of the frame as the profile, that is to say the strings come off the inside of the frame, this allows the stones that form the corners of the wall head to be placed corner to corner with the profile. Using lengths of steel re-enforcing bar driven in to the ground as profiles can be far more versatile than frames, as they can be adapted to any width or height of wall, whereas a frame once made is only good for that size and profile of wall. The procedure to set up a profile using these bars is as follows; firstly run a base line along the foundations of the existing wall for about two or three metres, this line should then be extended out from the end of the wall along the new foundation trench to where the new wall head is to be built. This line now gives you a starting point from which you can measure the width of the wall. Next hammer the bars in to the ground at the appropriate width for the wall you are building, make sure they are well in and firm as you will need to rely on them all day. Now you will need to measure the correct height for the wall and mark it vertically on the bars. This height is usually measured from the base of the foundation trench to the top of the wall under the copings. Once the height has been determined and marked on the bars the tops need to be secured at the right width, this can be done with wooden clamps but again like the spirit level this, in my opinion, is another element to waste time and indeed something else to have to carry around. If the bars are driven in to the ground near the vertical and then a piece of string tied to one of them at the correct height of the wall this string can be wrapped around the second pin and the two drawn together until the desired width at the top is achieved. The fact that the bars were driven in vertically and have now been drawn in at the top means they are under a slight tension which will help to hold them securely. Finally just eye through the bars from the end to make sure the batter matches that of the existing wall and check the bars are vertical; this can be done by eyeing them through to some nearby structure such as the end of a barn, a building, telegraph post etc there is usually something available as a vertical reference point, if not you will have to run to the car for the pesky spirit level! One last check and you are ready to go.
When building the wall head obviously the direction in which the stones are laid will alternate from course to course i.e. a tie stone running the full width of the wall head across its face and then two stones running along the length of the wall on either side, tying the wall head into the body of the wall. This process is then repeated course by course until the section of wall is completed. It does not really matter what direction the first stones are laid in the base of the wall head, a lot will depend on what is available on the day, although I always feel it is nice to start off with a good, big tie stone across the wall if possible. When you have placed a tie stone, the two runners that are then placed on top of it must reach back in to the adjacent wall as far as possible therefore tying the wall head securely in to the body of the wall. If there is a gap between these runners when the wall head is viewed from the front or head on it must be filled with a stone or sometimes two. It is essential that these stones in the face of the wall head are solid and tight as the examiners will check them. It is also important that they are level and do not protrude up above the level of the two runners as this would interfere with the placement of the next tie stone across them. When the top of the wall head is reached ensure you have a suitably large stone available to sit on the top of it, this will act as a support for the coping.
In the Intermediate Certificate, as well as the wall head, the examiners will be looking for a much higher level of finish than in the earlier Initial Certificate, this level of finish will be reflected in the marks for batter and camber and line and straightness. Both these elements of the test can be attained by firstly the correct positioning of the frames or profiles as explained above and secondly by the diligent use of string lines. In coursed work the lines should be lifted to the correct height of the selected course thickness at the start of every course. In random work they should be lifted to a height that suits the stone being used, in both cases you should never wall above the lines. Lines are there as a guide for you to work to; make sure they are tight and you use them, they will make a difference, string lines are of no use if they are dangling loose around your ankles. When your lines are in place and you are ready to commence work always begin a course from the wall head end as the last stone placed on the wall head will denote the thickness of that course. It is far easier to work away from the wall head in sequence than to randomly place stones on the wall.
As with all the other DSWA certificates the Intermediate Certificate consists of a timed test of seven hours duration, it is therefore important to pace your work accordingly. The DSWA has always believed that all its practical tests require a time constraint, this is to demonstrate that successful candidates can produce a set amount of work to a pre determined standard in a realistic time scale. This is essential if as a craftsman you are to be economically viable, further to this I am not aware of any test or exam situation where the examiner or invigilator arrives and declares ” take as long as you like, I’m here for as long it takes”. With this in mind it is well worth considering arranging a mock test so you can become accustomed to working under the pressure of a real test situation. As with the Initial test a candidate will need only to work to the required standard which may well be a lower standard than they are capable of , but remember it is an Intermediate level test, it does not require advanced level work. Time is the enemy in all these tests, so work efficiently.
So to recap, taking what was learned at the initial level regarding how the scheme is marked, to stripping out, working quickly and safely, now you will need to consider setting out and placing frames or profiles. Remember to work to string lines and to adjust their height when required, this will help you attain a more professional level of finish to your work. The wall head must be vertical, contain no loose stone, have an even batter on both sides but most importantly be well tied back into the adjacent wall.
The DSWA Intermediate Certificate is a tough certificate to attain, but it is achievable with practice and determination. All the wallers that have taken the test and passed it should be rightly proud, if this were an easy test it would be worth a lot less.