I have owned my BISF house for nearly 20 years, but only recently become aware of lead paint, most obviously on the outside walls, window and door frames, but also as it turns out, on internal walls and ceilings.
I have long relied on the advice on this forum, but I now realise there is no mention of safe working with lead when undertaking renovations - for example, when repairing external walls, the advice is to sand paint back to provide a good key, which while no doubt necessary for paint adhesion, is surely dangerous. How have others managed this risk?
Hi Emma, and welcome to what is actually a really important conversation that's been overdue on this forum — you're absolutely right to raise it, and you're definitely not alone in having managed a BISF for years without fully getting to grips with the lead paint question.
First, the reassuring bit: the fact that you've lived there comfortably for 20 years without incident is entirely consistent with how lead paint behaves when it's stable. Lead paint sealed under subsequent coats, or sitting intact on sound external render, isn't actively harming anyone. The risk arises when it's disturbed — and that's exactly where your instinct about sanding is spot on.
So you’ve hit on the single most important point regarding lead paint safety: dry sanding is the primary hazard. While traditional decorating advice always starts with "sand back to a key," when we're dealing with a BISF house (or any pre-1980s non-traditional build), that advice has to be modified to keep you and your family safe.
Here is how we manage that risk without compromising the quality of any renovation. Before I start though, it's worth emphasising that lead paint can and is found in all post-war buildings and dwellings across the world. It's certainly not just related to system-built housing in the UK. A 1950's brick built bungalow would have been painted with lead based gloss paint in its day too, which is just as concerning.
1. The BISF Context: Where the Lead Is
In a BISF house, you have three main areas of concern:
The Steel Frame and Panels: These were almost always factory-primed with Red Lead (lead tetroxide) for corrosion resistance. If you are going right back to the metal on the external profile sheet cladding or internal stanchions, you will almost certainly encounter this.
Woodwork and Metalwork: Windows, doors, and skirting boards from the original build are very likely to have lead-based primers and undercoats.
Walls and Ceilings: While less common on large plaster surfaces, lead was often used in "oil-bound" paints for kitchens and bathrooms or as a primer for the original hardboard/fibreboard internal linings.
2. The "Wet Sanding" Solution
The forum's advice to "provide a key" is still technically correct for paint adhesion, but for lead-safe working, we use Wet Abrasive Paper.
How it works: Use waterproof sandpaper (usually black/grey) and a bucket of water with a little detergent. Keep the surface and the paper wet at all times.
Why it’s safe: The water captures the paint particles, turning them into a "slurry" instead of airborne dust. Dust is what you can breathe in; slurry stays on the surface or the paper.
Clean up: Wipe the slurry away with damp cloths while it's still wet. Never let it dry out on the floor or windowsills.
3. Safe Removal Options
If the paint is flaking and must come off, dry scraping or power sanding is out. Instead, consider:
Chemical Strippers: These are excellent for BISF metalwork. They "lock" the lead into a paste or gel, which you then scrape off. Look for modern "peel-away" systems that keep the waste contained.
Controlled Heat: If you use a heat gun, it must be set below 500°C. Above this temperature, lead begins to give off toxic fumes. Never use a blowlamp or gas torch on a BISF house—not only because of the lead but because of the various cavity materials and potential fire risks in the frame.
4. The Power of Overpainting (Encapsulation)
The HSE and British Coatings Federation are very clear: If the paint is in good condition, leave it alone. Overpainting (encapsulation) is often the safest and most practical route.
If the original paint isn't flaking, just wash it down with sugar soap (which provides a mild chemical etch) and use a high-quality modern primer (like Zinsser BIN or a dedicated lead encapsulant) to seal it before your topcoat.
5. Essential Safety Protocol
Whenever you're disturbing suspected lead paint, please follow these "Golden Rules":
Protect the Area: Use heavy-duty plastic sheeting, not old sheets (which let dust through).
PPE: Wear a disposable overall and, crucially, an FFP3-rated face mask. Standard "dust masks" from the DIY shop won't stop lead particles.
Clean-up: Use a vacuum with a HEPA filter. A standard Henry or domestic vacuum will just blow the lead dust back out into the room. Follow up with a "wet-wipe" of all surfaces.
Protect the Family: Keep children and pregnant women out of the work area entirely until it has been thoroughly wet-cleaned.
Summary for your BISF project
Don't be alarmed—thousands of us live in these houses perfectly safely. The lead is only a problem when it's turned into dust or fumes. By switching from dry sanding to wet sanding or chemical stripping, you’ve already eliminated the biggest risk.
Are you planning to tackle the external steel panels soon if you still have them exposed, or are you starting with the internal woodwork?
Apologies for the delay in responding too Emma, I've been away out of action for a few months but I'm back now. I will also take a look back at some of our previous advice to ensure that we incorporate this valuable safety information.
Regards and special thanks for staying with us so long.
Marc