Non-combustible stainless steel helical insulation fixings for EWI and soffits

Price excl. VAT
Price incl. VAT
(15 items in stock)

Metal insulation fixings for fireproof insulation boards and panels. Superior insulation fasteners with twice the performance of friction-fix tube anchors.

Insofast-35 fixings have a 35mm perforated head.  A dome-shaped reinforcing centre is attached to a patented precise pitch Thor Helical shank to corkscrew into a variety of building materials including concrete, brick, perforated brick, Thermalite block. Theses metal fasteners are suitable for fixing mineral wool insulation to masonry walls and concrete soffit boards in all applications where fire-resistance is required. Also suitable for fixing Kingspan or Celotex panels where external wall insulation includes rendalath, expamet  or other mesh types.
Insofast-35 fixings are available in 304 grade Stainless Steel.

110mm insulation fixings for 40-70mm insulation boards
145mm insulation anchors for 75-105mm insulation slabs
170mm fireproof fixings for 105-130mm insulation panels
200mm metal fasteners for 135-160mm insulation boards

Twistfix sell Insofast-35 metal insulation fixings in packs of 20. For fixing insulation boards drill 5mm ( brick) or 6mm ( concrete) pilot hole 10mm longer than the anchor and hammer at least 40mm into masonry. No pilot hole required for fixing the fasteners to Thermalite or Celcon blocks

Delivery options are only available for delivery to mainland UK (excluding Scottish Highlands, Scottish Islands, Channel Islands, Isle Of Man Northern Ireland and Eire). Delivery to Scottish Highlands, Scottish Islands, Channel Islands, Isle Of Man, Northern Ireland and Eire are limited to 20kg and are available at a Premium rate. Please contact us on or via our help line if delivery is required outside these areas. Alternatively select ‘World-wide Delivery’ and a member of our sales staff will contact you regarding your options and costs.


We offer for the mainland UK , as standard, a FREE delivery service on all orders having a value greater than £200.00 (excluding VAT). For orders having a value less than £200.00 (excluding VAT) a carriage fee of £8.50 + VAT will be levied. Goods will be sent by a national carrier on their 1-2 working day standard service. Customers must understand that delays can always happen while their order is with the courier, for this reason we can not guarantee your order will be with you next day.

It is important that the customer ensures that all the delivery details are correct and that the customer or someone acting for the customer is able to sign for the delivery. Twistfix accept no liability for failed deliveries as a result of incorrect delivery details or the absence of any authorised signatory. Twistfix will attempt delivery to the recipient between the hours of between 8am and 6pm. If no one is available to receive the delivery an attempt may be made to leave the item with a neighbour. Alternatively the carrier may return the item to the sorting office and leave a calling card at the recipient's address to advise of the attempted delivery. It is the responsibility of the customer to arrange to collect the item from the depot or to arrange re-delivery with the carrier. Further information regarding Delivery can be read at our Terms & Conditions.


Items returned and received in their original condition and packaging within 14 days of delivery will be accepted for exchange or refund subject to a 20% restocking fee. You will be responsible for the shipping costs incurred in returning the goods and should ensure the items are adequately insured while in transit to us. You should email to request to return items.

Where the goods are being returned because they are faulty or are not the goods that were ordered then, subject to the goods being returned in re-saleable condition, Twistfix will refund the cost of return shipping. Further information regarding Returns can be read at our Terms & Conditions.