What if one doesn't have sound home environment without stressors?
I think if your home environment is actually traumatic, then it's not possible to do effective trauma therapy at the same time.
Regarding stressors, I'm not sure. I've been doing trauma therapy around all sorts of home stressors (such as major building repair work, minor vandalism and issues with neighbours) as well as other life stressors (such workplace bullying, legal and financial issues, very difficult contact with relatives). It makes it harder but if I'd waited until things were more stable then I'd never do the trauma work.
To some extent it's a Catch 22. There's a point where I can't move forward and make my home environment more stable until I've worked through various things with trauma work. In the meantime I live where I live, with the life that I have. So how else am I going to do trauma work?
I think what's most important is building up a lot of resources and good coping skills, and using them. I think the home environment needs to be stable enough. What "enough" means will vary from person to person, but I'd suggest that even when dealing with other stressors, there may be a way to do effective trauma work. For me, that has included creating some quiet space the evening after therapy and the following morning, however disrupted and stressful the rest of the week might be. It has also included careful pacing of the trauma work. I have lots of sessions inbetween that are focussed on regrouping, coping and general life issues.
Maybe it's different with EMDR, but from discussions on the forum it sounds to me like the potentially destabilising and other difficult reactions are similar to the ones that I have.
When I say a lot of coping and safety skills, I really mean a lot. During trauma work, I personally think they need to be done almost all the time, and to be done proactively and not just in reaction to things coming up. We have to do them consistently whether we feel able to do them or not. I think the home environment needs to be without trauma, and as stable as it can be, but for me the most fundamental point about doing trauma work is having strong inner resources and strategies, and using them.