The envelope as a system of assemblies
A building envelope is the set of assemblies that separates inside from outside: walls, roofs, floors and the junctions between them. Insulation sits within those assemblies, alongside framing, linings and finishes, and its performance depends on the assembly as a whole rather than on any single layer. Glass wool is presented for building envelopes among its applications, and rock wool is presented for building assemblies, and both routes should be read at assembly level for envelope work.
An envelope enquiry should therefore describe the assemblies involved, wall, roof or floor, together with the layers, framing and finishes that surround the insulation. A requirement stated without an assembly cannot be answered reliably, and an assembly stated without a requirement cannot be judged. Both facts belong in the enquiry, in that order, for each assembly under discussion.
Forms in envelope assemblies
Batts suit framed wall and roof assemblies, where pieces are fitted between members. Blankets suit larger envelope surfaces and wraps, where a flexible layer must follow a shape or cover an area. Boards suit flat runs within envelope assemblies, where a firm layer is laid against a surface or within a build-up. Each form raises its own fixing and junction questions, and those questions should be stated in the enquiry for each assembly.
A batt enquiry should state the frame or cavity it must fit. A blanket enquiry should state the area and the shape it must follow. A board enquiry should state the surface and how the board will be held in place. Those facts let the discussion stay on the assembly rather than drifting into general material talk, and they help the supplier match forms to the assemblies named.
Envelope questions worth asking
Useful envelope questions include: how the insulation sits within each assembly, layer by layer; how junctions between wall, roof and floor are handled; how penetrations for services are treated; and how moisture and air movement around the assemblies are considered. Each of those questions should be tied to a named assembly, since an answer for a wall may not apply to a roof. An enquiry that ties questions to named assemblies will receive a more direct answer than one that asks about envelopes in general terms.
Setting facts also matter: whether the building is new or existing, whether the assemblies are accessible for fixing and later inspection, and whether the work is phased across assemblies. Each of those facts should be stated in the enquiry, since fixing, sequencing and quantities often differ with the setting and the phase of work.
From envelope description to an order
Once the assemblies, the forms and the envelope questions are known, the remaining questions are commercial and documentary: quantity terms, timing, trade terms, payment method and documents for the items named. None of those points is stated as a catalogue fact on this site, and each should be asked for the items named in the enquiry. Documents follow the same order: items first, documents second, with the general wording that certificates are available upon request.
An enquiry that follows that order, assembly first, then form, then question, then commercial and document questions, will produce answers that can be checked against the order. The general checklist collects those questions in order for buyers who want a drafting aid before the form is sent.
Certificates available upon request. Please confirm the minimum order quantity in your inquiry before placing an order. Please confirm the lead time with the supplier before placing an order. Please confirm the trade terms and payment method before confirming an order.