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Building Assembly Guidelines



Please note it is advised you only take on the assembly of our buildings if you have previous general building experience, we are happy to give additional advice during your assembly should you require it, please allow 24 hour for enquiries to be answered as we do not have a dedicated assembly advice team, our sales team will need time to double check with the relavant team to ensure we give you the correct advise. Instructions for assmebly include the below instructions plus some additional figures for you specific building.  

To help you make your decision please read the below guidelines, these will be supplied to you with additional figures of your building to assist you with assembly.
Please note your building is custom made to order bespoke item and does not come with mass produced flat pack furniture style instructions, this is a cold rolled steel building not a wardrobe after all.

Assembly Instructions for a Small Steel Garage or Shed

The tools you will need:-


1. Electric drill/screwdriver (the rechargeable/cordless type is best);
2. Hammer drill;
3. 20mm masonry drill bit;
4. 8mm socket driver to fit your drill/screwdriver;
5. Electric extension lead;
6. Selection of spanners (typically 13-19mm and sockets if possible) and/or suitable impact wrench fittings;
7. A good socket set;
8. General hand tools such as: hammer, screwdrivers, nail bar, pliers, tin snips, adjustable spanner, rubber hammer, hand file, etc;
9. Angle grinder (9” is best, though a 4.5” may suffice);
10. Safe working platform, such as a small tower scaffold or better still a scissor lift;
11. Step ladder or steps x 2;
12. Roofing ladder, duct board or other means of working on a roof safely;
13. Various HSS drill bits (typically an 8.5mm);
14.  Spirit level;
15. Rivet gun;
16. Gutter sealant if you’ve ordered gutters.

What you should have in the kit provided unless otherwise arranged. (These will be detailed in the packing list provided with your building)

Assembling the structural steel frame:

Your building will ultimately be supported by a number of steel truss and leg assemblies, and a number of gable and/or door legs (see figure 1 which depicts the whole frame less the wall and roof beams which are shown in part only for clarity).

Once you are familiar with the parts, after studying the parts list, have identified what is what and have marked out approximately where each leg will be finally positioned - you are ready to start building. 


Please note: All of the structural steel parts are bolted using 8mm bolts, washers and nuts.



The first step is to bolt all the corner brackets to the legs, away from your construction area.

Next rivet all the water intrusion angles, base plates and base plate joining brackets together for the whole building and accurately position the assembly using the key dimensions shown in figure 2. Once you are satisfied with the positioning of the water intrusion angles, drill and bolt down the masonry brackets into the concrete (2 x bolts per masonry bracket). You will now have a firm foundation to start adding your structural framework to.

Water Intrusion Angles (figure 6) are designed to give you a surface to apply a suitable water sealant (like a liquid rubber product) around the perimeter of your building prior to fixing panels to help stop water ingress into your building. The ability to gain a good quality seal will depend on how well your concrete foundation has been laid.

It is recommended that you bolt the masonry brackets into the concrete base, working from the middle outwards.  This will make any small adjustments that may have to be made whilst working outwards less noticeably.  Once you have two sets bolted into the ground add the legs to the anchor plates and appropriate wall and eave beams.  Do the opposite side of the building and complete the whole truss and leg assembly.  You can now add the roof beams to these two assemblies which will give you a firm basis to finish adding the rest of the assemblies in a similar fashion.

Once all truss assemblies are upright - go back and add any beams that you have left out along the length of the building (roof and wall), until all the wall and roof beams are in place.  This will ensure the whole building is ridged.

For reference (on standard assemblies): each truss and leg assembly consists of two uprights (legs), each finishing with a corner bracket (triangular profiled bracket), into which attach the roof trusses. 

On standard pitched roof designs: roof trusses are joined in the middle by a flat bottomed bracket with the two upper sides angled (to the roof pitch).



The next step is to add any gable legs so that you can add the rest of the wall beams to the gable ends of the building.  Gable legs are positioned on the building as displayed (in figures 3a and 3b) and are attached to the buildings end trusses using gable brackets (figure 4).

Eave beams are designed to be bolted over the corner of the building (as in figure 5) and are manufactured to bolt into the top of each bay.

Normal beams for the wall and roof are shown in (figure 7).



During the whole construction you should be working closely with a good spirit level ensuring everything is positioned square however once you have the complete frame assembly constructed, you should ensure that the whole building is completely squared off and vertical, once more.  You can determine if the structure is square, by measuring across the diagonals from opposite corner to opposite corner (or by using the 3-4-5 triangle rule (adjacent, opposite and hypotenuse)).  These measurements should be within 5mm of each other, or as close as you can get.  The condition of your ground (and more to the point how level your foundation is) will determine how accurate you ultimately can be.  You should check that all the legs are vertical using a good spirit level.  At this stage, you can still move the structure by pressing your weight against it at the appropriate place, as the bolt connections will still flex slightly under load.  Once you have attached your first wall sheet, the structure will be fixed in position and will not flex anymore.  Before you attach your first sheet, you should take particular care to ensure that the frame assembly is as square, level and positioned as accurately as possible.  One additional benefit of the obround bolt holes is to give you a little movement in your fixings.  If necessary loosen your structural bolts off and slide them to one end of the obround to help level your frame. 

TOP TIP: You may find that the spring in the steel of certain truss & leg assemblies forces them off vertical once pressure is removed from them, in which case a lorry/ratchet strap is a great way of holding the building vertical whilst you fit the panels (just ensure you fit it in a way you can remove once the panels are on). 


Once you are perfectly happy with the frame, you should position and drill any remaining masonry bolts before you start to fix the wall sheets.  This is best done by working your way from one end of the building to the other.


PLEASE NOTE: On lean to style constructions it is paramount that you use wall fixings which are suitable for the style of construction you are fixing the props/trusses to.  If unsure please consult a qualified person - for your own safety.


Fitting Doors:

Up and Over Door Installation:

-          These doors are designed to fit "behind the aperture” as described in the separate door installation instructions. The up and over door bolts behind the gable legs as shown (in figure 1). 

-          Please follow the separate up and over door instructions for full install advice.


Roller Door Installation:

-          These doors are designed to fit behind the aperture of the opening.

-          Please use the appropriate figure for reference on part positioning.

-          Please follow the separate roller door instructions (found within your roller door wrapping) for full install advice.

Pedestrian Doors:

-          These are designed to fit between the door post legs.  You will need to mark and drill the door posts through the 20mm holes in the door frame.  It is not usually necessary to bolt the top of the door frame, only the sides of the frame.  Pedestrian doors should be installed after the exterior panels of the building have been affixed to either side of the door.  To confirm the position the door needs to located, hold the pedestrian door side flashings temporarily in place, against the cladding and then offer the door up to the rear of the flashing.  This will ensure that the door is set the right distance back from the exterior face of the wall.


Fixing the wall sheets:

The wall sheets are fixed using the self-drilling (L32W16B) fixing screws provided.  You will note there are two types of self-drilling screws.  One has a fine thread and is used to fix the wall/roof sheets to the steel frame.  One has a course thread (S22W16B).  These are stitching screws and are used to fix a sheet to a sheet or flashing to sheet.  Do not confuse the two.  The stitching screws will tend to snap if you use them to fix the sheets to the frame.

You will notice that the sheets have a left and a right side.  One side has only a partially completed profile while one side has a fully completed profile.  It is important that the partial profile goes under the full profile side.  With this in mind, start at one corner of your building and fix the sheets first along a long wall (not the gables), as this will ensure the building is square.  Fix the sheets by screwing through them with the self-drilling fixing screws so that you use one fixing screw in every other channel on the sheet ensuring that you fix to every wall beam available equally, including the floor beam and eave beam.  The appearance of your building will be greatly enhanced if you take care to put all the screws in the same line and in the same channels. 

Continue in this way along the whole wall until you reach the next corner.  Make sure that your first sheet is perfectly vertical before you fix it and that each subsequent sheet is pushed tightly down over the overlap of the previous sheet.  While each sheet covers exactly 1000mm width, it is actually 1070mm wide.  This is to allow for the overlap.  It also means that your last sheet will invariably need to be trimmed down with an angle grinder to be the right width for your wall.

TOP TIP: use one of the bend lines in your panel as your cut line and clearly mark along this with a felt-tipped pen (as this will remain visible when you cut).  Your grinder will naturally follow this line – giving you a straight cut.

You should proceed to sheet the gable walls in just the same way as you sheeted the side walls, but you will need to cut the top slope of each sheet to match with your roof.  You should do this by offering the sheet up to the frame and marking each side at the top of the truss, then connect the marks with a straight line and cut the surplus off with an angle grinder or circular saw (with a metal cutting blade).  Don’t worry if you are not perfect with these cuts, they are covered by the flashings when you attach them. 

Warning! You should be very careful in your choice of which gable wall sheet to cut and be sure you have identified each one correctly before you cut it.  They are all of different lengths as the slope of the roof rises.  If you cut the wrong one for a particular position, the next sheet will be too short.

We often provide panels for the gable ends in a length suitable to get two panels – one for each end of the gable.  This reduces the wastage and number of cuts that have to be made.  So if your panels are far longer than you expect this is the reason why.


Fixing the Roof Sheets:

The roof sheets are the same profile as the walls (albeit sometimes with the colour on the opposite side). 

If you’ve ordered them - first decide where you intend to put your GRP translucent roof light sheets.  The roof-light sheets come in factory set lengths so you will have to trim them appropriately – the rest of your steel roof sheets are supplied in the correct length.

Once you have decided on the positioning of the GRP sheets, you should start sheeting the roof from one end.

Be very careful when placing the first and second roof sheets.  The overhang at the eave edge should be around 100mm the edge must be exactly parallel with the wall.  The long edge should not overhang the gable wall sheets but be flush or slightly set back from their outside edge. 

TOP TIP: only put one screw initially into the first sheet so you can pivot the sheet if needs be, when you place the second sheet.  Once you are happy that the overhang is exactly parallel to the wall, you can then fix the roof sheets in the same way as you fixed the wall sheets. 

Once again, you will probably need to trim the last sheet to fit the building, so it doesn’t overhang the gable wall.


Fixing the flashings:

The flashings are designed to seal the building and eliminate the ingress of draughts and water.  All but some of the door flashings are secured with stitching screws to the high points on the roof and wall profiles.  Basically if your screwing into cladding only, use stitching screws, any screws which will go through thicker steel need to be self-drilling ones.  The door drips (above the door) should be slid under the wall sheet above the door, then fixed using the self-drilling steel screws used to fix the sheet to the lintel beam.

All the flashings are labelled and should be self-evident.  They go on the corners, ridge, over the gable ends and roof and around the doors.  If you have ordered gutters your gutters act as the flashing down the length of the building otherwise you will have eave flashings to seal the length edges.  For logistic reasons some lengths of flashings, e.g. the ridge are provided in multiple pieces - we recommend using around a 400mm overlap.

Some foam profile strips have been supplied to seal the gap between the ridge flashing and the roof sheet.  This should be pressed under the ridge flashing before the stitching screws are tightened down.  If you prefer to keep a vent here to allow air flow in your building, you can leave these foam fillers out.  Similarly push foam fillers under the roof panel and above the eave flashing - if you didn’t order gutters or if you did order box gutters place the foam fillers between the eave beam and roof panel and use expanding foam (not supplied) between the eave beam and wall sheet if desired.  If you are worried about condensation or later find it to be a problem – try removing the foam fillers from the eave and ridge as this may help relieve the issue.

For lean to style constructions the ridge flashing has been supplied in two pieces.  The larger flashing sits on your roof and the smaller is designed to be fitted into the mortar line of brickwork and over the larger flashing.


Finishing your building off:

Plastic screw head cover-caps have been supplied in your colour choice to cover the exposed screw heads.

If you would like your building to be water tight at ground level, one option is to make a 4/1 mix of sharp sand and cement plus some water proofing agent and form a 4” angle fillet all around the outside base of your building.

We hope you will get many years of use from your new building.  Every part has been manufactured from high grade fully galvanised steel and should last many years without undue sign of aging.  Spare parts can be obtained from us should you ever need them. 

Thank you for ordering your building from us.



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