Build a messaging framework

I work in marketing at a construction firm. Help me build a simple messaging framework for the firm.

Context: Estimators, contracts managers and directors describe the firm differently in each bid. One agreed page stops the website, the tender answers and the prequalification forms drifting apart.

Before you start, ask me for anything missing from this list:
- Who we help
- What we do and how it differs
- Proof for each claim

Then:
1. Write one sentence that says who we help and how.
2. Add three supporting messages with proof.
3. List phrases to use and to avoid.

Give me:
- A one-page framework
- A 25-word and a 50-word description of the firm

Rules:
- Use only the facts I give you. Where something is missing, write [detail needed]. Never invent a number, a name, a quote or a source.
- Describe building work in general terms only. Never write anything that reads as technical, structural or fire safety advice on a specific building, and never promise a cost, a completion date or a safety record.
- Write in plain English, in our voice if I have given you a sample.
- Do not tell me what the rules or regulations say. If something may be restricted, flag it and I will check.

Finish with a list headed "Check before this goes out". Include these, plus anything else the director who approves marketing or our health, safety and quality lead should see:
- Proof behind each claim, in a form a tender evaluator would accept
- Use of sustainable, safe, accredited and specialist
- Director agreement before it is used in bids