Board Backed and All Board Envelopes

What Are Board Backed Envelopes?

Board backed envelopes, sometimes called hard backed envelopes or hardback envelopes, are postal envelopes with a stiff cardboard panel on the reverse side. The front of the envelope is standard paper, while the back provides a rigid surface that prevents the contents from bending, creasing or folding during transit. Most board backed envelopes are printed with the words “Please Do Not Bend” to alert postal workers to handle them with care.

Board backed envelopes are lighter and more economical than all board envelopes, making them the standard choice for everyday document mailing where one-sided rigidity is sufficient.

What Are All Board Envelopes?

All board envelopes are made entirely from solid board on both sides, providing rigid protection on the front and the back. Unlike board backed envelopes, which have a paper front and a card back, all board envelopes offer maximum resistance to bending and crushing from any direction.

This makes them the preferred choice for more valuable or fragile flat items such as original artwork, photographs, mounted prints and important certificates where even minor damage is unacceptable. They are also a good option when items are being posted without any additional internal packaging.

Board Backed vs All Board: Which Do You Need?

The choice between board backed and all board envelopes depends on what you are sending and how much protection it requires:

Board backed envelopes are the right choice for most everyday document mailing. Contracts, certificates, brochures, reports and printed materials all benefit from the rigid cardboard backing, and the lighter weight keeps postage costs down. They are the most popular and economical option for businesses that post flat items regularly.

All board envelopes are the better option when the contents are particularly valuable or fragile. Original artwork, photographs, mounted prints and items that cannot tolerate any bending or pressure benefit from the full rigidity that solid board provides on both sides. They cost a little more per unit, but offer a level of protection that board backed envelopes cannot match.

If you are unsure which type is right for your needs, our team can help you choose. Call us on 01326 564331 or request a free sample of each to compare them side by side.

Available Sizes

We stock board backed envelopes in three sizes and all board envelopes in two sizes, each designed to match standard paper sizes and Royal Mail’s Pricing in Proportion (PiP) guidelines:

Board Backed Envelopes

C4 (324 x 229mm) holds A4 documents unfolded. This is the most popular size for posting contracts, certificates, brochures, reports and A4 artwork. Packed in boxes of 125.

C5 (229 x 162mm) holds A5 documents or A4 sheets folded in half. Ideal for smaller mailings such as greetings cards, invoices or half-fold brochures. Packed in boxes of 125.

C5+ (240 x 165mm) is slightly wider than a standard C5, giving a little more room for thicker documents or items that need a fraction more space. Packed in boxes of 125.

All Board Envelopes

C4 (324 x 229mm) holds A4 documents unfolded. Fully rigid on both sides, ideal for artwork, photographs and important printed materials. Packed in boxes of 100.

C5 (229 x 162mm) holds A5 documents or A4 sheets folded in half. Suitable for greetings cards, prints and smaller fragile items. Packed in boxes of 200.

All sizes fall within Royal Mail’s large letter or letter thresholds, helping to keep postage costs manageable.

Do Not Bend Envelopes for Documents and Flat Items

If you regularly post documents, certificates, photographs or printed materials that must arrive in perfect condition, do not bend envelopes are an essential part of your despatch supplies. The rigid cardboard construction prevents creasing, folding and corner damage that can occur with standard paper envelopes, particularly on longer postal journeys or when items pass through automated sorting equipment.

Board backed and all board envelopes are widely used by schools, solicitors, accountants, estate agents, print shops, photographers and any business that sends flat paperwork or artwork to clients. They are also popular with e-commerce sellers despatching greetings cards, prints and other flat products that need to arrive in pristine condition.

Strong, Sustainable Cardboard Envelopes

All of our board backed, and all board envelopes are made using cardboard from FSC or PEFC approved sustainable sources. They are fully recyclable in standard cardboard and paper waste streams and are biodegradable, making them a responsible choice for businesses looking to reduce their packaging footprint.

The peel and seal closure on both types means there is no need for tape or moisture, keeping packing times short and ensuring a clean, professional finish on every envelope.

Why Buy Board Backed and All Board Envelopes from Forms Plus?

Forms Plus have supported businesses with their printing and packaging requirements since 1981. We stock board backed envelopes in C4, C5 and C5+ sizes, and all board envelopes in C4 and C5, with most lines available for same day despatch. Our pricing is competitive and transparent, with further discounts available on larger orders.

If you need cushioned protection rather than rigidity, see our Padded Envelopes which are bubble lined for items that need cushioning against bumps and drops. We also supply Eco Padded Envelopes for a plastic free alternative, and a full range of Postal Boxes for bulkier items.

Request a Free Sample or Contact Our Team if you would like help choosing the right envelope for your needs.