M3016 – Hinged Door Frame Assembly

The door frame (CODF) comprises of 7 pieces of 100mm x 47mm x 3m timber which are for the 4 door frame posts and door frame lintel. The remaining pieces supplied in the pack are 19mm x 38mm x 1.8m battens which are used later when fitting your polytunnel cover.

Start by running a taut string line across the width on the inside of your polytunnel on the end hoop. Determine the centre of your polytunnel width by measuring 15ft from the corner hoop from the centre of the tube. From this central position, measure 1.14m towards each corner hoop. From the central position now measure 2.2m toward each corner hoop. This identifies the position of your four door posts. If you are fitting your polytunnel onto an earth base you will be required to excavate a hole 30cm square and 40cm deep. If fitting to a solid base such as concrete or timber the door frame posts will be secured to the ground using brackets

Install the two inner door frame post first. Reposition one of the door frame post into the hole or onto the solid base ensuring the front face of the post is behind the string line. Ensure the door frame post is positioned 1.14m from the centre mark to the inside of the door frame post (fig 14a). The two inner door frame posts will be fitted to the rear of the door rail. They will exceed the top of the door rail and will be required to cut down after fitting. To secure the top of the door frame post to the door rail, fit a P clip onto the door rail (fig 14b). The prongs of the P clip should run down the rear of the door rail and fix to the front face of the door frame post where it is held in place with bolts and mark the holes through the P clips. Using a 9mm wood drill bit, drill through the timber on the marks. Push a bolt through the P clip and drilled holes so that the thread is on the inside of the polytunnel, loosely secure with a washer and nut (fig 14c). When securing to the ground, ensure that the door frame post is positioned 1.14m from the centre mark to the inner edge of the door frame post. It is critical that the door frame post is vertical, use a spirit level on the front and side face of the post. Once you are happy with the position tighten the nuts on the P clip and secure the P clip in place with a self-drilling screw.

If on soil, backfill the hole with concrete. We suggest using concrete that is 1 part cement and 5 part aggregate. We also recommend ‘PostCrete’. This ready-made mix is supplied in 20kg bags, requires no mixing, you simply add water. Approximately one bag per hole will be required. To secure to concrete, mark the position of the door frame post plates on the inside of the polytunnel (fig 14d). Fix the base of the post plate to the floor using Shield Anchors. Use a 16mm masonry drill bit to drill 75mm down, separate the shield from the bolt and place the shield in the hole. Reposition the post plate and use the bolts with a 17mm socket to secure in position. Secure the post plate to the door frame post using the screws supplied (fig 14e).

If on a timber base, fix the base of the plate to the floor using Coach Screws. Position the door frame post plate on the ground on the inside of your polytunnel, make a mark through the centre hole then remove. Drill a pilot hole 7cm deep using a 9mm timber drill bit. Reposition the post plate and tighten the coach screw using a 17mm spanner. Finally, screw the plate to the door post using the screws provided. Cut of the excess of the inner door frame post off inline with the top of the door rail.

To fit the door post ensure you leave the concrete for an adequate amount of time to set. Position the T hinge internally onto the door frame post, ensure the chamfered holes are visible. Use the screws provided in the commercial door frame kit to secure the hinged to the door post. Position the door ensuring there is enough ground clearance for the door to fully open and close. With the first inner door post and door fitted we will move on to fit the second. Position the second door post in the hole and loosely fix it to the door rail with a P clip (fig 14f). Temporarily screw two self-drilling screw  in to the edge of the door, this will ensure there is a consistent gap between the two doors and enable them to open and shut properly.

Have one person hold the second door up to the first one and then adjust the door post. Once the door post is tight up to the door secure it in place by screwing the hinges onto the door post. It is critical that the door frame post is vertical, use a spirit level on the front and side face of the post. With everything in the correct position, firmly tighten the nuts on the P clip and secure the P clip in place with a self-drilling screw. Secure the door frame post to the floor using the method demonstrated earlier. Check that both of your doors can open with enough ground clearance. If needed, adjust the height of the doors accordingly. You can now remove the self-drilling screws (SDS55).

Install the two outer door frame posts. These are to provide additional strength to the door structure. The two outer door frame posts will need to be cut to size prior to securing them as they are fitted under the door rail. Position an outer door frame post into the hole or onto the solid base, ensure the door frame post is vertical using a spirit level. Mark the uprights of the door post under the door rail. Cut the post on this mark. Reposition the outer door frame post ensuring the inner edge of the door frame post is 2.2m from the central position (fig 14g).

Fit a P clip onto the door rail (P50). Both prongs of the P Clip should then run down the front face of the door post where it is held in place with bolts. Make a mark through the 2 holes of the P clip. Using a 9mm wood drill bit, drill a hole through the 2 marks. Push a bolt through the P clip and drilled holes so that the thread is on the inside of the polytunnel, loosely secure with a washer and nut. When securing to the ground, ensure that the door frame post is positioned 2.2m from the centre mark to the inner edge of the door frame post. It is critical that the door frame post is vertical, use a spirit level on the front and side face of the post. Once you are happy with the position tighten the nuts on the P clip and secure the P clip in place with a self-drilling screw. Secure the door frame post to the floor using the method demonstrated earlier. Secure the second outer door frame post using the same method.

The door lintel is supplied in 2 pieces of 100mm x 50mm timber 3 meters long. The lintel spans between the two outer door frame posts and runs across the front face of the inner posts. Butt the two pieces of door lintel up together and join them together by using right-angled joiners placed on opposite corners with twisted nails (fig 14h). Approximately 30 nails per plate will suffice. The door frame lintel should be set 5mm above the top of the door and the bottom edge of the lintel. Offer the door frame lintel up, position one end flush with one door post and make a mark at the other end and cut. Reposition the lintel, ensure the door fame lintel is level and use a 4mm wood drill bit to drill a pilot hole. Use a 150mm screw to secure to the door post. Repeat at the other side.

On the inner posts drill a 9mm hole through both the lintel and the inner post, push a 110mm M8 (DPT2) cup square bolt through the drilled hole so that the thread is on the inside of the polytunnel, fit the washer and screw on a nut then tighten (fig 14i). The joints can now be reinforced with nail plates on both sides. Position a nail plate equally across the joint and secure in place with twisted nails. Now fit the base timber. This piece of timber is between the door post and the outer door post. Position a piece of 100mm x 47mm timber so it butts up with the outside edge of the inner door frame post and runs past the outer face of the outer frame door post. Make a mark on the base timber where it reaches the outside edge of the outer door frame post and cut on this mark.To secure the base timber to the door posts drill a hole, using a 4mm drill bit, through the inner doorpost in line with the base timber and screw the two together with a 150mm screw.

On the outer post drill a 9mm hole through both the outer door frame post and the base timber. Push a 110mm M8 (DPT2) cup square bolt through the drilled hole so that the thread is on the inside of the polytunnel, fit the washer and screw on a nut then tighten. The joints can now be reinforced with nail plates on both sides. Position a nail plate equally across the joint and secure in place with twisted nails. Repeat this for the base timber on the opposite side.

Finally fit the door drop spikes that keep your door from blowing in the wind. Door drop spikes are fitted to the outside face of the door on the opposite side to the hinges. Measure up from the bottom of the door 9cm and make a mark (fig 14j). Position a door drop spike guide bracket so the bottom of the bracket is flush with this mark. Mark the position of the 2 slots in the bracket and across the top. Now reposition the bracket so the bottom of the bracket is flush with the top mark and mark the position of the 2 slots again. Using a 9mm wood drill bit, drill a hole through the door for the 4 slots. On the inside face of the door insert pronged T nuts into each hole. Bolt the 2 angled brackets to the door with the slot on each bracket at the top. Close the door to the required position, slide the drop spike down through both brackets and mark the position on the ground. Open the door and bury the tube in the required position (fig 14k). If your polytunnel is on a hard base the housing tube is not required. Simply drill a hole using a 9mm drill bit to an appropriate depth.