Far from an expert but I would say adding a moisture based cement product over wood is about the worst possible thing you could do. The only thing he is guaranteeing is that the rest of the trim that was not already replaced with an injected foam trim will be very soon.

Given the fact that stucco is not waterproof and wood is moisture sensitive, I would be hesitant with this approach. That said, I am confessing that I have never done or seen this done.

Thanks. You both have great points I didn't consider. Is there any other way to achieve the same look?

What he ^^^^^^^ said........

Thank you both!

Yep most builders i know use fypon

Could Hardietrim be used to fill in where the wood came out, or is it too thin? Could it be placed over if filled in like in the picture? I'm not too keen on styrofoam trim. But I have the same problem as the house featured here -- the old wood trim has to go, and I'm worried if I just have the area filled in with stucco, the finish might not match well enough or it might crack.

Hardie does not play well with water. Edge swells. Should be PVC of the materials that are readily available.

Windows on Washington Ltd That's scary about Hardietrim. Thanks. Do you have an opinion on stuccoing in all the way up to the window instead of trim?

Don't care for that option, but stucco is not big around here. The issue is that windows move at differential rates to the stucco and it will be easy to form cracks and water entry pathways. A proper Z-head flashing trim and some composite PVC trim around the perimeter is probably the most prove and easily deployed option.