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Ground anchors to fix down Polytunnels

Polytunnels come in many different sizes from very low cost hobby types, through medium size and on up aircraft hanger sizes. Our anchors are not designed to secure large industrial types but they are ideal for small and medium polytunnels.

Most frames are made from round steel tube and we offer a range of clamp fittings up to 51mm (2") to suit.

Low cost polytunnels are often supplied with securing pegs, however to keep the package weight and cost down, any supplied pegs are likely to be no more than small tent pegs which might work if the tunnel is sited in a very protected position but not otherwise. In most cases, you will have to provide your own anchors.

Our polytunnel fixings use the standard, lowest cost Erdanker anchor together with a clamp type bracket, no drilling is needed, and they can be removed if needed and re-used any number of times.

When deciding which anchor and clamp to use, firstly measure the tube diameter, see the 2 illustrations below, and ensure you meaure accurately, the brackets will work with tubes less than the specified size but not with larger sizes, do not rely on any advertised specification as actual sizes can vary wildly, also note that cross tubes, floor tubes, upright tubes, could be different but similar sizes.

Next you must decide on the appropriate anchor and how many to use. There are many factors involved including: size and style of polytunnel, soil conditions, potential wind conditions etc. In theory, any size anchor can be used with any size clamp, but most contractors use the 30x440ED and 30x540ED for tubes up to 30mm, the 40x680ED for tubes up to 38mm and the 50x800ED for tubes up to 51mm. If you have soft, sandy soil, you may need larger or longer anchors, for very hard ground, the smaller anchors will be fine. They are likely to be needed on the 4 corners and except for small tunnels, on some of the intermediates as well.

Do not overtighten the clamps, especially on very thin wall tubes or with aluminium as the grip is more than enough at moderate tightness and any more can sqash the tube. Ensure the bolt ends of the clamp are not against the pvc cover and protect the cover where it might rub against the bracket.

Measuring the tube.

Measuring the tube, this method is accurate The correct way (measuring the end of the tube)

Incorrect method of measuring Incorrect way (measurement is not accurate)

E29 - E51 brackets

E bracket from above     E bracket


It is generally simpler to fit anchors before covering, but not essential.


 Anchor types

 Erdanker® Standard
 Anchors and Fittings